Charging system and charging method, and power adapter

ABSTRACT

The present disclosure discloses a charging system and a charging method and a power adapter. The system includes a battery, a first rectifier, a switch unit, a transformer, a second rectifier, a sampling unit and a control unit. The control unit outputs a control signal to the switch unit, and adjusts a duty ratio of the control signal according to a current sampling value and/or a voltage sampling value sampled by the sampling unit, such that a third voltage with a third ripple waveform outputted by the second rectifier meets a charging requirement. The third voltage is configured to be introduced into the battery.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of an InternationalApplication No. PCT/CN2016/091758, filed on Jul. 26, 2016, which isbased upon and claims priority to International Application No.PCT/CN2016/073679, filed on Feb. 5, 2016, the entire contents of whichare incorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a terminal technical field,and more particularly, to a charging system, a charging method, and apower adapter.

BACKGROUND

Nowadays, mobile terminals such as smart phones are favored by more andmore consumers. However, the mobile terminal consumes large powerenergy, and needs to be charged frequently.

Typically, the mobile terminal is charged by a power adapter. The poweradapter generally includes a primary rectifier circuit, a primary filtercircuit, a transformer, a secondary rectifier circuit, a secondaryfilter circuit and a control circuit, such that the power adapterconverts the input alternating current of 220V into a stable and lowvoltage direct current (for example, 5V) suitable for requirements ofthe mobile terminal, and provides the direct current to a powermanagement device and a battery of the mobile terminal, therebyrealizing charging the mobile terminal.

However, with the increasing of the power of the power adapter, forexample, from 5 W to larger power such as 10 W, 15 W, 25 W, it needsmore electronic elements capable of bearing large power and realizingbetter control for adaptation, which not only increases a size of thepower adapter, but also increases a production cost and manufacturedifficulty of the power adapter.

SUMMARY

Embodiments of a first aspect of the present disclosure provide acharging system. The charging system includes a battery, a firstrectifier, configured to rectify an input alternating current and outputa first voltage with a first ripple waveform; a switch unit, configuredto modulate the first voltage according to a control signal and output amodulated first voltage; a transformer, configured to output a secondvoltage with a second ripple waveform according to the modulated firstvoltage; a second rectifier, configured to rectify the second voltage tooutput a third voltage with a third ripple waveform; a sampling unit,configured to sample current outputted by the second rectifier to obtaina current sampling value; and a control unit, coupled to the samplingunit and the switch unit respectively, and configured to output thecontrol signal to the switch unit, and to control a charging process tobe in a constant current charging stage by adjusting a duty ratio of thecontrol signal when it is determined that current outputted is high orlow according to the current sampling value. The third voltage isapplied to the battery.

Embodiments of a second aspect of the present disclosure provide a poweradapter. The power adapter includes: a first rectifier, configured torectify an input alternating current and output a first voltage with afirst ripple waveform; a switch unit, configured to modulate the firstvoltage according to a control signal and output a modulated firstvoltage; a transformer, configured to output a second voltage with asecond ripple waveform according to the modulated first voltage; asecond rectifier, configured to rectify the second voltage to output athird voltage with a third ripple waveform, in which the third voltageis configured to be introduced into a terminal to charge a battery inthe terminal when the power adapter is coupled to the terminal; asampling unit, configured to sample current outputted by the secondrectifier to obtain a current sampling value; and a control unit,coupled to the sampling unit and the switch unit respectively, andconfigured to output the control signal to the switch unit, and tocontrol a charging process performed by the power adapter on a terminalto be in a constant current charging stage by adjusting a duty ratio ofthe control signal when it is determined that current outputted by thepower adapter is high or low according to the current sampling value.

Embodiments of a third aspect of the present disclosure provide acharging method. The charging method includes: when a power adapter iscoupled to a terminal, performing a first rectification on a firstalternating current to output a first voltage with a first ripplewaveform; modulating the first voltage by controlling a switch unit, andoutputting a second voltage with a second ripple waveform by aconversion of a transformer; performing a second rectification on thesecond voltage to output a third voltage with a third ripple waveform,and applying the third voltage to a battery of the terminal; samplingcurrent after the second rectification to obtain a current samplingvalue; controlling a charging process performed by the power adapter onthe terminal to be in a constant current charging stage by adjusting aduty ratio of a control signal for controlling the switch unit when itis determined that current outputted by the power adapter is high or lowaccording to the current sampling value.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram illustrating a charging system using aflyback switching power supply according to an embodiment of the presentdisclosure.

FIG. 1B is a schematic diagram illustrating a charging system using aforward switching power supply according to an embodiment of the presentdisclosure.

FIG. 1C is a schematic diagram illustrating a charging system using apush-pull switching power supply according to an embodiment of thepresent disclosure.

FIG. 1D is a schematic diagram illustrating a charging system using ahalf-bridge switching power supply according to an embodiment of thepresent disclosure.

FIG. 1E is a schematic diagram illustrating a charging system using afull-bridge switching power supply according to an embodiment of thepresent disclosure.

FIG. 2 is a block diagram of a charging system according to embodimentsof the present disclosure.

FIG. 3 is a schematic diagram illustrating a waveform of a chargingvoltage outputted to a battery from a power adapter according to anembodiment of the present disclosure.

FIG. 4 is a schematic diagram illustrating a waveform of a chargingcurrent outputted to a battery from a power adapter according to anembodiment of the present disclosure.

FIG. 5 is a schematic diagram illustrating a control signal outputted toa switch unit according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram illustrating a second charging processaccording to an embodiment of the present disclosure.

FIG. 7A is a schematic diagram illustrating a charging system accordingto an embodiment of the present disclosure.

FIG. 7B is a schematic diagram illustrating a power adapter with a LCfilter circuit according to an embodiment of the present disclosure.

FIG. 8 is a schematic diagram illustrating a charging system accordingto another embodiment of the present disclosure.

FIG. 9 is a schematic diagram illustrating a charging system accordingto yet another embodiment of the present disclosure.

FIG. 10 is a schematic diagram illustrating a charging system accordingto still another embodiment of the present disclosure.

FIG. 11 is a block diagram of a sampling unit according to an embodimentof the present disclosure.

FIG. 12 is a schematic diagram illustrating a charging system accordingto still yet another embodiment of the present disclosure.

FIG. 13 is a schematic diagram illustrating a terminal according to anembodiment of the present disclosure.

FIG. 14 is a schematic diagram illustrating a terminal according toanother embodiment of the present disclosure.

FIG. 15 is a flow chart of a charging method according to embodiments ofthe present disclosure.

DETAILED DESCRIPTION

Descriptions will be made in detail to embodiments of the presentdisclosure, examples of which are illustrated in drawings, in which thesame or similar elements and the elements having same or similarfunctions are denoted by like reference numerals throughout thedescriptions. The embodiments described herein with reference todrawings are explanatory, are intended to understand the presentdisclosure, and are not construed to limit the present disclosure.

The present disclosure is made based on following understanding andresearches.

The inventors find that, during a charging to a battery of a mobileterminal by a power adapter, with the increasing of power of the poweradapter, it is easy to cause an increase in polarization resistance ofthe battery and temperature of the battery, thus reducing a service lifeof the battery, and affecting a reliability and a safety of the battery.

Moreover, most devices cannot work directly with alternating currentwhen the power is usually supplied with the alternating current, becausethe alternating current such as mains supply of 220V and 50 Hz outputselectric energy discontinuously. In order to avoid the discontinuity, itneeds to use an electrolytic condenser to store the electric energy,such that when the power supply is in the trough period, it is possibleto depend on the electric energy stored in the electrolytic condenser toensure a continue and stable power supply. Thus, when an alternatingcurrent power source charges the mobile terminal via the power adapter,the alternating current such as the alternating current of 220V providedby the alternating current power source is converted into stable directcurrent, and the stable direct current is provided to the mobileterminal. However, the power adapter charges the battery in the mobileterminal so as to supply power to the mobile terminal indirectly, andthe continuity of power supply can be guaranteed by the battery, suchthat it is unnecessary for the power adapter to output stable andcontinue direct current when charging the battery.

Accordingly, a first objective of the present disclosure is to provide acharging system, which enables a voltage with a ripple waveformoutputted by a power adapter to be applied to a battery of the terminaldirectly, thus realizing a miniaturization and low cost of the poweradapter, and prolonging a service life of the battery.

A second objective of the present disclosure is to provide a poweradapter. A third objective of the present disclosure is to provide acharging method.

In the following, a charging system, a power adapter and a chargingmethod provided in embodiments of the present disclosure will bedescribed with reference to drawings.

Referring to FIGS. 1A-14, the charging system may include a battery 202,a first rectifier 101, a switch unit 102, a transformer 103, a secondrectifier 104, a sampling unit 106, and a control unit 107.

The first rectifier 101 is configured to rectify an input alternatingcurrent and output a first voltage with a first ripple waveform. Theswitch unit 102 is configured to modulate the first voltage according toa control signal and output a modulated first voltage. The transformer103 is configured to output a second voltage with a second ripplewaveform according to the modulated first voltage. The second rectifier104 is configured to rectify the second voltage to output a thirdvoltage with a third ripple waveform. The sampling unit 106 isconfigured to sample current outputted by the second rectifier to obtaina current sampling value. The control unit 107 is coupled to thesampling unit 106 and the switch unit 102 respectively. The control unit107 is configured to output the control signal to the switch unit 102,and to control a charging process to be in a constant current chargingstage by adjusting a duty ratio of the control signal when it isdetermined that current outputted is high or low according to thecurrent sampling value. The third voltage is applied to the battery 202.

In at least one embodiment of the present disclosure, part or allstructure (hardware and software) of the adapter can be integrated intothe terminal Integrated structure of the adapter and the terminal can becalled as the charging system of the present disclosure, or called as aterminal.

In an embodiment of the present disclosure, the charging system providedin embodiments of the present disclosure includes a power adapter 1 anda terminal 2. The battery may be a component in a terminal 2. The firstrectifier, the switch unit, the transformer, the second rectifier, thesampling unit and the control unit may be disposed in a power adapter 1.

As illustrated in FIG. 2, the power adapter 1 includes the firstrectifier 101, the switch unit 102, the transformer 103, the secondrectifier 104, the sampling unit 106 and the control unit 107. The firstrectifier 101 is configured to rectify an input alternating current(mains supply, for example AC 220V) to output a first voltage with afirst ripple waveform, for example a voltage with a steamed bunwaveform. As illustrated in FIG. 1A, the first rectifier 101 may be afull-bridge rectifier circuit formed of four diodes. The switch unit 102is configured to modulate the first voltage with the first ripplewaveform according to a control signal to output a modulated firstvoltage. The switch unit 102 may be formed of MOS transistors. A PWM(Pulse Width Modulation) control is performed on the MOS transistors toperform a chopping modulation on the voltage with the steamed bunwaveform. The transformer 103 is configured to output a second voltagewith a second ripple waveform according to the modulated first voltage.The second rectifier 104 is configured to rectify the second voltage tooutput a third voltage with a third ripple waveform, in which the thirdvoltage is configured to be introduced into a terminal to charge abattery in the terminal when the power adapter is coupled to theterminal. The second rectifier 104 may be formed of diodes or MOStransistors, and can realize a secondary synchronous rectification, suchthat the third ripple waveform keeps synchronous with a waveform of themodulated first voltage. It should be noted that, the third ripplewaveform keeping synchronous with the waveform of the modulated firstvoltage means that, a phase of the third ripple waveform is consistentwith that of the waveform of the modulated first voltage, and avariation trend of magnitude of the third ripple waveform is consistentwith that of the waveform of the modulated first voltage. The samplingunit 106 is configured to sample current outputted by the secondrectifier 104 to obtain a current sampling value. The control unit 107is coupled to the sampling unit 106 and the switch unit 102respectively, and configured to output the control signal to the switchunit 102, and to control a charging process performed by the poweradapter 1 to the terminal 2 to be in a constant current charging stageby adjusting a duty ratio of the control signal when it is determinedthat current outputted by the power adapter is high or low according tothe current sampling value.

It should be noted that, when the current outputted by the power adapter1 is high or low, a peak current/a mean current of the third ripplewaveform outputted by the second rectifier 104 is higher or lower than acurrent reference value of the constant current charging stage, i.e.higher or lower than the current reference value of the constant currentcharging stage by a certain preset value.

Further, in an embodiment of the present disclosure, the power adapterfurther includes a first charging interface 105. The first charginginterface 105 is coupled to the second rectifier 104. The first charginginterface 105 is configured to apply the third voltage to the battery inthe terminal via a second charging interface of the terminal when thefirst charging interface 105 is coupled to the second charginginterface, in which the second charging interface is coupled to thebattery.

As illustrated in FIG. 2, the terminal 2 includes a battery 202. Thethird voltage is configured to be introduced into a terminal to charge abattery in the terminal when the power adapter is coupled to theterminal.

In an embodiment, the terminal 2 further includes a second charginginterface 201. The second charging interface 201 is coupled to thebattery 202. When the second charging interface 201 is coupled to thefirst charging interface 105, the second charging interface 201 isconfigured to apply the third voltage with the third ripple waveform tothe battery 202, so as to charge the battery 202.

In an embodiment of the present disclosure, the control unit 107 isconfigured to reduce the duty ratio of the control signal when thecurrent outputted by the power adapter 1 is high, such that the currentoutputted by the power adapter 1 is reduced to the current referencevalue. The control unit 107 is configured to increase the duty ratio ofthe control signal when the current outputted by the power adapter 1 islow, such that the current outputted by the power adapter 1 is increasedto the current reference value.

In an embodiment of the present disclosure, the sampling unit 106 isfurther configured to sample voltage outputted by the second rectifier106 to obtain a voltage sampling value. After the constant currentcharging stage is completed, the control unit 107 is further configuredto control the charging process performed by the power adapter 1 to theterminal 2 to be in a constant voltage charging stage by adjusting theduty ratio of the control signal when it is determined that voltageoutputted by the power adapter is high or low according to the voltagesampling value.

In an embodiment, when the voltage outputted by the power adapter 1 ishigh or low, a peak voltage/a mean voltage of the third ripple waveformoutputted by the second rectifier 104 is higher or lower than a voltagereference value of the constant voltage charging stage, i.e. higher orlower than the voltage reference value of the constant voltage chargingstage by a certain preset value.

The control unit 107 is configured to reduce the duty ratio of thecontrol signal when the voltage outputted by the power adapter 1 ishigh, such that the voltage outputted by the power adapter 1 is reducedto the voltage reference value. The control unit 107 is configured toincrease the duty ratio of the control signal when the voltage outputtedby the power adapter is low, such that the voltage outputted by thepower adapter 1 is increased to the voltage reference value.

In an embodiment of the present disclosure, as illustrated in FIG. 1A,the power adapter 1 may employ a flyback switching power supply. Indetail, the transformer 103 includes a primary winding and a secondarywinding. An end of the primary winding is coupled to a first output endof the first rectifier 101. A second output end of the first rectifier101 is grounded. Another end of the primary winding is coupled to theswitch unit 102 (for example, if the switch unit 102 is a MOStransistor, the other end of the primary winding is coupled to a drainof the MOS transistor). The transformer 103 is configured to output asecond voltage with a second ripple waveform according to the modulatedfirst voltage.

The transformer 103 is a high-frequency transformer of which a workingfrequency ranges from 50 KHz to 2 MHz. The high-frequency transformer isconfigured to couple the modulated first voltage to the secondary sideso as to output via the secondary winding. In embodiments of the presentdisclosure, with the high-frequency transformer, a characteristic of asmall size compared to the low-frequency transformer (also known as anindustrial frequency transformer, mainly used in the frequency of mainssupply such as alternating current of 50 Hz or 60 Hz) may be exploitedto realize miniaturization of the power adapter 1.

In an embodiment of the present disclosure, as illustrated in FIG. 1B,the power adapter 1 may also adopt a forward switching power supply. Indetail, the transformer 103 includes a first winding, a second windingand a third winding. A dotted terminal of the first winding is coupledto a second output end of the first rectifier 101 via a backward diode.A non-dotted terminal of the first winding is coupled to a dottedterminal of the second winding and then coupled to a first output end ofthe first rectifier 101. A non-dotted terminal of the second winding iscoupled to the switch unit 102. The third winding is coupled to thesecond rectifier 104. The backward diode is configured to realizereverse peak clipping. An induced potential generated by the firstwinding may perform amplitude limiting on a reverse potential via thebackward diode and return limited energy to an output of the firstrectifier 101, so as to charge the output of the first rectifier 101.Moreover, a magnetic field generated by current flowing through thefirst winding may demagnetize a core of the transformer, so as to returnmagnetic field intensity in the core of the transformer to an initialstate. The transformer 103 is configured to output the second voltagewith the second ripple waveform according to the modulated firstvoltage.

According to an embodiment of the present disclosure, as illustrated inFIG. 1C, the above-mentioned power adapter 1 may adopt a push-pullswitching power supply. In detail, the transformer includes a firstwinding, a second winding, a third winding and a fourth winding. Adotted terminal of the first winding is coupled to the switch unit 102.A non-dotted terminal of the first winding is coupled to a dottedterminal of the second winding and then coupled to the first output endof the first rectifier 101. A non-dotted terminal of the second windingis coupled to the switch unit 102. A non-dotted terminal of the thirdwinding is coupled to a dotted terminal of the fourth winding. Thetransformer is configured to output the second voltage with the secondripple waveform according to the modulated first voltage.

As illustrated in FIG. 1C, the switch unit 102 includes a first MOStransistor Q1 and a second MOS transistor Q2. The transformer 103includes a first winding, a second winding, a third winding and a fourthwinding. A dotted terminal of the first winding is coupled to a drain ofthe first MOS transistor Q1 in the switch unit 102. A non-dottedterminal of the first winding is coupled to a dotted terminal of thesecond winding. A node between the non-dotted terminal of the firstwinding and the dotted terminal of the second winding is coupled to thefirst output end of the first rectifier 101. A non-dotted terminal ofthe second winding is coupled to a drain of the second MOS transistor Q2in the switch unit 102. A source of the first MOS transistor Q1 iscoupled to a source of the second MOS transistor Q2 and then coupled tothe second output end of the first rectifier 101. A dotted terminal ofthe third winding is coupled to a first input end of the secondrectifier 104. A non-dotted terminal of the third winding is coupled toa dotted terminal of the fourth winding. A node between the non-dottedterminal of the third winding and the dotted terminal of the fourthwinding is grounded. A non-dotted terminal of the fourth winding iscoupled to a second input end of the second rectifier 104.

As illustrated in FIG. 1C, the first input end of the second rectifier104 is coupled to the dotted terminal of the third winding, and thesecond input end of the second rectifier 104 is coupled to thenon-dotted terminal of the fourth winding. The second rectifier 104 isconfigured to rectify the second voltage with the second ripple waveformand to output the third voltage with the third ripple waveform. Thesecond rectifier 104 may include two diodes. An anode of one diode iscoupled to the dotted terminal of the third winding. An anode of anotherdiode is coupled to a non-dotted terminal of the fourth winding. Acathode of one diode is coupled to that of the other diode.

According to an embodiment of the present disclosure, as illustrated inFIG. 1D, the above-mentioned power adapter 1 may also adopt ahalf-bridge switching power supply. In detail, the switch unit 102includes a first MOS transistor Q1, a second MOS transistor Q2, a firstcapacitor C1 and a second capacitor C2. The first capacitor C1 and thesecond capacitor C2 are coupled in series, and then coupled in parallelto the output ends of the first rectifier 101. The first MOS transistorQ1 and the second MOS transistor Q2 are coupled in series, and thencoupled in parallel to the output ends of the first rectifier 101. Thetransformer 103 includes a first winding, a second winding and a thirdwinding. A dotted terminal of the first winding is coupled to a nodebetween the first capacitor C1 and the second capacitor C2 coupled inseries. A non-dotted terminal of the first winding is coupled to a nodebetween the first MOS transistor Q1 and the second MOS transistor Q2coupled in series. A dotted terminal of the second winding is coupled tothe first input end of the second rectifier 104. A non-dotted terminalof the second winding is coupled to a dotted terminal of the thirdwinding, and then grounded. A non-dotted terminal of the third windingis coupled to the second input end of the second rectifier 104. Thetransformer 103 is configured to output the second voltage with thesecond ripple waveform according to the modulated first voltage.

According to an embodiment of the present disclosure, as illustrated inFIG. 1E, the above-mentioned power adapter 1 may also adopt afull-bridge switching power supply. In detail, the switch unit 102includes a first MOS transistor Q1, a second MOS transistor Q2, a thirdMOS transistor Q3 and a fourth MOS transistor Q4. The third MOStransistor Q3 and the fourth MOS transistor Q4 are coupled in series andthen coupled in parallel to the output ends of the first rectifier 101.The first MOS transistor Q1 and the second MOS transistor Q2 are coupledin series and then coupled in parallel to the output ends of the firstrectifier 101. The transformer 103 includes a first winding, a secondwinding and a third winding. A dotted terminal of the first winding iscoupled to a node between the third MOS transistor Q3 and the fourth MOStransistor Q4 coupled in series. A non-dotted terminal of the firstwinding is coupled to a node between the first MOS transistor Q1 and thesecond MOS transistor Q2 coupled in series. A dotted terminal of thesecond winding is coupled to the first input end of the second rectifier104. A non-dotted terminal of the second winding is coupled to a dottedterminal of the third winding, and then grounded. A non-dotted terminalof the third winding is coupled to the second input end of the secondrectifier 104. The transformer 103 is configured to output the secondvoltage with the second ripple waveform according to the modulated firstvoltage.

Therefore, in embodiments of the present disclosure, the above-mentionedpower adapter 1 may adopt any one of the flyback switching power supply,the forward switching power supply, the push-pull switching powersupply, the half-bridge switching power supply and the full-bridgeswitching power supply to output the voltage with the ripple waveform.

Further, as illustrated in FIG. 1A, the second rectifier 104 is coupledto the secondary winding of the transformer 103. The second rectifier104 is configured to rectify the second voltage to output the thirdvoltage with the third ripple waveform. The second rectifier 104 may beformed of diodes, and can realize a secondary synchronous rectification,such that the third ripple waveform keeps synchronous with a waveform ofthe modulated first voltage. It should be noted that, the third ripplewaveform keeping synchronous with the waveform of the modulated firstvoltage means that, a phase of the third ripple waveform is consistentwith that of the waveform of the modulated first voltage, and avariation trend of magnitude of the third ripple waveform is consistentwith that of the waveform of the modulated first voltage. The firstcharging interface 105 is coupled to the second rectifier 104. Thesampling unit 106 is configured to sample current and/or voltageoutputted by the second rectifier 104 to obtain a current sampling valueand/or a voltage sampling value. The control unit 107 is coupled to thesampling unit 106 and the switch unit 102 respectively, and configuredto output the control signal to the switch unit 102, and to adjust theduty ratio of the control signal according to the current sampling valueand/or the voltage sampling value, such that the third voltage outputtedby the second rectifier 104 meets the charging requirement.

As illustrated in FIG. 1A, the terminal 2 includes a second charginginterface 201 and a battery 202. The second charging interface 201 iscoupled to the battery 202. When the second charging interface 201 iscoupled to the first charging interface 105, the second charginginterface 201 is configured to apply the third voltage with the thirdripple waveform to the battery 202, so as to charge the battery 202.

In an embodiment, the third voltage with the third ripple waveformmeeting the charging requirement means that, the third voltage andcurrent with the third ripple waveform need to meet the charging voltageand charging current when the battery is charged. In other words, thecontrol unit 107 is configured to adjust the duty ratio of the controlsignal (such as a PWM signal) according to the sampled voltage and/orcurrent outputted by the power adapter, so as to adjust the output ofthe second rectifier 104 in real time and realize a closed-loopadjusting control, such that the third voltage with the third ripplewaveform meets the charging requirement of the terminal 2, thus ensuringthe stable and safe charging of the battery 202. In detail, a waveformof a charging voltage outputted to a battery 202 is illustrated in FIG.3, in which the waveform of the charging voltage is adjusted accordingto the duty ratio of the PWM signal. A waveform of a charging currentoutputted to a battery 202 is illustrated in FIG. 4, in which thewaveform of the charging current is adjusted according to the duty ratioof the PWM signal.

In an embodiment, when adjusting the duty ratio of the PWM signal, anadjusting instruction may be generated according to the voltage samplingvalue, or according to the current sampling value, or according to thevoltage sampling value and the current sampling value.

Therefore, in embodiments of the present disclosure, by controlling theswitch unit 102, a PWM chopping modulation is directly performed on thefirst voltage with the first ripple waveform i.e. the steamed bunwaveform after a rectification, and then a modulated voltage is sent tothe high-frequency transformer and is coupled from the primary side tothe secondary side via the high-frequency transformer, and then ischanged back to the voltage/current with the steamed bun waveform aftera synchronous rectification. The voltage/current with the steamed bunwaveform is directly transmitted to the battery so as to realize fastcharging (which is described as the second charging in the following) tothe battery. The magnitude of the voltage with the steamed bun waveformmay be adjusted according to the duty ratio of the PWM signal, such thatthe output of the power adapter may meet the charging requirement of thebattery. It can be seen from that, the power adapter according toembodiments of the present disclosure, without providing electrolyticcondensers at the primary side and the secondary side, may directlycharge the battery via the voltage with the steamed bun waveform, suchthat a size of the power adapter may be reduced, thus realizingminiaturization of the power adapter, and decreasing cost greatly.

In an embodiment of the present disclosure, the control unit 107 may bean MCU (micro controller unit), which means that the control unit 107may be a micro processor integrated with a switch driving controlfunction, a synchronous rectification function, a voltage and currentadjusting control function.

According to an embodiment of the present disclosure, the control unit107 is further configured to adjust a frequency of the control signalaccording to the voltage sampling value and/or the current samplingvalue. That is, the control unit 107 is further configured to control tooutput the PWM signal to the switch unit 102 for a continuous timeperiod, and then to stop outputting for a predetermined time period andthen to restart to output the PWM signal. In this way, the voltageapplied to the battery is intermittent, thus realizing the intermittentcharging of the battery, which avoids a safety hazard caused by heatingphenomenon occurring when the battery is charged continuously andimproves the reliability and safety of the charging to the battery.

Under a low temperature condition, since the conductivity of ions andelectrons in a lithium battery decreases, it is prone to intensifydegree of polarization during a charging process for the lithiumbattery. A continuous charging not only makes this polarization seriousbut also increases a possibility of lithium precipitation, thusaffecting safety performance of the battery. Furthermore, the continuouscharging may accumulate heat generated due to the charging, thus leadingto an increasing of internal temperature of the battery. When thetemperature exceeds a certain value, performance of the battery may belimited, and possibility of safety hazard is increased.

In embodiments of the present disclosure, by adjusting the frequency ofthe control signal, the power adapter outputs intermittently, whichmeans that a battery resting process is introduced into the chargingprocess, such that the lithium precipitation due to the polarizationduring the continuous charging is reduced and continuous accumulation ofgenerated heat may be avoided to realize drop in the temperature, thusensuring the safety and reliability of charging to the battery.

The control signal outputted to the switch unit 102 is illustrated inFIG. 5, for example. Firstly, the PWM signal is outputted for acontinuous time period, then output of the PWM signal is stopped for acertain time period, and then the PWM signal is outputted for acontinuous time period again. In this way, the control signal output tothe switch unit 102 is intermittent, and the frequency is adjustable.

As illustrated in FIG. 1A, the control unit 107 is coupled to the firstcharging interface 105. The control unit 107 is further configured toobtain status information of the terminal 2 by performing acommunication with the terminal 2 via the first charging interface 105.In this way, the control unit 107 is further configured to adjust theduty ratio of the control signal (such as the PWM signal) according tothe status information of the terminal, the voltage sampling valueand/or the current sampling value.

The status information of the terminal includes an electric quantity ofthe battery, a temperature of the battery, a voltage of the battery,interface information of the terminal and information on a pathimpedance of the terminal.

In detail, the first charging interface 105 includes a power wire and adata wire. The power wire is configured to charge the battery. The datawire is configured to communicate with the terminal. When the secondcharging interface 201 is coupled to the first charging interface 105,communication query instructions may be transmitted by the power adapter1 and the terminal 2 to each other. A communication connection can beestablished between the power adapter 1 and the terminal 2 afterreceiving a corresponding reply instruction. The control unit 107 mayobtain the status information of the terminal 2, so as to negotiatedwith the terminal 2 about a charging mode and charging parameters (suchas the charging current, the charging voltage) and to control thecharging process.

The charging mode supported by the power adapter and/or the terminal mayinclude a first charging mode and a second charging mode. A chargingspeed of the second charging mode is faster than that of the firstcharging mode. For example, a charging current of the second chargingmode is greater than that of the first charging mode. In general, thefirst charging mode may be understood as a charging mode in which arated output voltage is 5V and a rated output current is less than orequal to 2.5 A. In addition, in the first charging mode, D+ and D− inthe data wire of an output port of the power adapter may beshort-circuited. On the contrary, in the second charging mode accordingto embodiments of the present disclosure, the power adapter may realizedata exchange by communicating with the terminal via D+ and D− in thedata wire, i.e., second charging instructions may be sent by the poweradapter and the terminal to each other. The power adapter sends a secondcharging query instruction to the terminal. After receiving a secondcharging reply instruction from the terminal, the power adapter obtainsthe status information of the terminal and operates in the secondcharging mode according to the second charging reply instruction. Thecharging current in the second charging mode may be greater than 2.5 A,for example, may be 4.5 A or more. The first charging mode is notlimited in embodiments of the present disclosure. As long as the poweradapter supports two charging modes one of which has a charging speed(or current) greater than the other charging mode, the charging modewith a slower charging speed may be regarded as the first charging mode.As to the charging power, the charging power in the second charging modemay be greater than or equal to 15 W.

The first charging mode is a normal charging mode and the secondcharging mode is a fast charging mode. Under the normal charging mode,the power adapter outputs a relatively small current (typically lessthan 2.5 A) or charges the battery in the mobile terminal with arelatively small power (typically less than 15 W). While, under the fastcharge mode, the power adapter outputs a relatively large current(typically greater than 2.5 A, such as 4.5 A, 5 A or higher) or chargesthe battery in the mobile terminal with a relatively large power(typically greater than or equal to 15 W), compared to the normalcharging mode. In the normal charging mode, it may take several hours tofully fill a larger capacity battery (such as a battery with 3000 mAh),while in the fast charging mode, the period of time may be significantlyshortened when the larger capacity battery is fully filled, and thecharging is faster.

The control unit 107 communicates with the terminal 2 via the firstcharging interface 105 to determine the charging mode. The charging modeincludes the second charging mode and the first charging mode.

In detail, the power adapter is coupled to the terminal via a universalserial bus (USB) interface. The USB interface may be a general USBinterface, or a micro USB interface. A data wire in the USB interface isconfigured as the data wire in the first charging interface, andconfigured for a bidirectional communication between the power adapterand the terminal The data wire may be D+ and/or D− wire in the USBinterface. The bidirectional communication may refer to an informationinteraction performed between the power adapter and the terminal.

The power adapter performs the bidirectional communication with theterminal via the data wire in the USB interface, so as to determine tocharge the terminal in the second charging mode.

In an embodiment, during a process that the power adapter and theterminal negotiate whether to charge the terminal in the second chargingmode, the power adapter may only keep a coupling with the terminal butdoes not charge the terminal, or charges the terminal in the firstcharging mode or charges the terminal with small current, which is notlimited herein.

The power adapter adjusts a charging current to a charging currentcorresponding to the second charging mode, and charges the terminal.After determining to charge the terminal in the second charging mode,the power adapter may directly adjust the charging current to thecharging current corresponding to the second charging mode or maynegotiate with the terminal about the charging current of the secondcharging mode. For example, the charging current corresponding to thesecond charging mode may be determined according to a current electricquantity of the battery of the terminal.

In embodiments of the present disclosure, the power adapter does notincrease the output current blindly for second charging, but needs toperform the bidirectional communication with the terminal so as tonegotiate whether to adopt the second charging mode. In contrast to therelated art, the safety of second charging is improved.

As an embodiment, when the control unit 107 performs the bidirectionalcommunication with the terminal via the first charging interface so asto determine to charge the terminal in the second charging mode, thecontrol unit 107 is configured to send a first instruction to theterminal and to receive a first reply instruction from the terminal Thefirst instruction is configured to query the terminal whether to operatein the second charging mode. The first reply instruction is configuredto indicate that the terminal agrees to operate in the second chargingmode.

As an embodiment, before the control unit sends the first instruction tothe terminal, the power adapter is configured to charge the terminal inthe first charging mode. The control unit is configured to send thefirst instruction to the terminal when determining that a chargingduration of the first charging mode is greater than a predeterminedthreshold.

In an embodiment, when the power adapter determines that the chargingduration of the first charging mode is greater than the predeterminedthreshold, the power adapter may determine that the terminal hasidentified it as a power adapter, such that the second charging querycommunication may start.

As an embodiment, after determining the terminal is charged for apredetermined time period with a charging current greater than or equalto a predetermined current threshold, the power adapter is configured tosend the first instruction to the terminal.

As an embodiment, the control unit is further configured to control thepower adapter to adjust a charging current to a charging currentcorresponding to the second charging mode by controlling the switchunit. Before the power adapter charges the terminal with the chargingcurrent corresponding to the second charging mode, the control unit isconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface to determine acharging voltage corresponding to the second charging mode, and tocontrol the power adapter to adjust a charging voltage to the chargingvoltage corresponding to the second charging mode.

As an embodiment, when the control unit performs the bidirectionalcommunication with the terminal via the data wire of the first charginginterface to determine the charging voltage corresponding to the secondcharging mode, the control unit is configured to send a secondinstruction to the terminal, to receive a second reply instruction sentfrom the terminal, and to determine the charging voltage correspondingto the second charging mode according to the second reply instruction.The second instruction is configured to query whether a current outputvoltage of the power adapter is suitable for being used as the chargingvoltage corresponding to the second charging mode. The second replyinstruction is configured to indicate that the current output voltage ofthe power adapter is suitable, high or low.

As an embodiment, before controlling the power adapter to adjust thecharging current to the charging current corresponding to the secondcharging mode, the control unit is further configured to perform thebidirectional communication with the terminal via the data wire of thefirst charging interface to determine the charging current correspondingto the second charging mode.

As an embodiment, when performing the bidirectional communication withthe terminal via the data wire of the first charging interface todetermine the charging current corresponding to the second chargingmode, the control unit is configured to send a third instruction to theterminal, to receive a third reply instruction sent from the terminaland to determine the charging current corresponding to the secondcharging mode according to the third reply instruction. The thirdterminal is configured to query a maximum charging current supported bythe terminal. The third reply instruction is configured to indicate themaximum charging current supported by the terminal.

The power adapter may determine the above maximum charging current asthe charging current corresponding to the second charging mode, or mayset the charging current as a charging current less than the maximumcharging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the control unit is furtherconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface, so as to continuouslyadjust a charging current outputted to the battery from the poweradapter by controlling the switch unit.

The power adapter may query the status information of the terminalcontinuously, for example, query the voltage of the battery of theterminal, the electric quantity of the battery, etc, so as to adjustcontinuously the charging current outputted by the power adapter to thebattery.

As an embodiment, when the control unit performs the bidirectionalcommunication with the terminal via the data wire of the first charginginterface to continuously adjust the charging current outputted to thebattery from the power adapter by controlling the switch unit, thecontrol unit is configured to send a fourth instruction to the terminal,to receive a fourth reply instruction sent by the terminal, and toadjust the charging current outputted by the power adapter to thebattery by controlling the switch unit according to the current voltageof the battery. The fourth instruction is configured to query a currentvoltage of the battery in the terminal. The fourth reply instruction isconfigured to indicate the current voltage outputted by the poweradapter to the battery in the terminal.

As an embodiment, the control unit is configured to adjust the chargingcurrent outputted to the battery from the power adapter to a chargingcurrent value corresponding to the current voltage of the battery bycontrolling the switch unit according to the current voltage of thebattery and a predetermined correspondence between battery voltagevalues and charging current values.

In detail, the power adapter may store the correspondence betweenbattery voltage values and charging current values in advance. The poweradapter may also perform the bidirectional communication with theterminal via the data wire of the first charging interface to obtainfrom the terminal the correspondence between battery voltage values andcharging current values stored in the terminal.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the control unit is furtherconfigured to determine whether there is a poor contact between thefirst charging interface and the second charging interface by performingthe bidirectional communication with the terminal via the data wire ofthe first charging interface. When determining that there is the poorcontact between the first charging interface and the second charginginterface, the control unit is configured to control the power adapterto quit the second charging mode.

As an embodiment, before determining whether there is the poor contactbetween the first charging interface and the second charging interface,the control unit is further configured to receive information indicatinga path impedance of the terminal from the terminal. The control unit isconfigured to send a fourth instruction to the terminal. The fourthinstruction is configured to query a current voltage of the battery inthe terminal The control unit is configured to receive a fourth replyinstruction sent by the terminal. The fourth reply instruction isconfigured to indicate the current voltage of the battery in theterminal The control unit is configured to determine a path impedancefrom the power adapter to the battery according to an output voltage ofthe power adapter and the current voltage of the battery and determineswhether there is the poor contact between the first charging interfaceand the second charging interface according to the path impedance fromthe power adapter to the battery, the path impedance of the terminal,and a path impedance of a charging wire between the power adapter andthe terminal.

The terminal may record the path impedance thereof in advance. Forexample, since the terminals in a same type have a same structure, thepath impedance of the terminals in the same type is set to a same valuewhen configuring factory settings. Similarly, the power adapter mayrecord the path impedance of the charging wire in advance. When thepower adapter obtains the voltage cross two ends of the battery of theterminal, the path impedance of the whole path can be determinedaccording to the voltage drop cross two ends of the battery and currentof the path. When the path impedance of the whole path>the pathimpedance of the terminal+the path impedance of the charging wire, orthe path impedance of the whole path−(the path impedance of theterminal+the path impedance of the charging wire)>an impedancethreshold, it can be considered that there is the poor contact betweenthe first charging interface and the second charging interface.

As an embodiment, before the power adapter quits the second chargingmode, the control unit is further configured to send a fifth instructionto the terminal. The fifth instruction is configured to indicate thatthere is the poor contact between the first charging interface and thesecond charging interface.

After sending the fifth instruction, the power adapter may quit thesecond charging mode or reset.

The second charging process according to embodiments of the presentdisclosure is described from the perspective of the power adapter, andthen the second charging process according to embodiments of the presentdisclosure will be described from the perspective of the terminal in thefollowing.

In an embodiment, the interaction between the power adapter and theterminal, relative characteristics, functions described at the terminalside correspond to descriptions at the power adapter side, thusrepetitive description will be omitted for simplification.

According to an embodiment of the present disclosure, as illustrated inFIG. 13, the terminal 2 further includes a charging control switch 203and a controller 204. The charging control switch 203, such as a switchcircuit formed of an electronic switch element, is coupled between thesecond charging interface 201 and the battery 202, and is configured toswitch on or off a charging process of the battery 202 under a controlof the controller 204. In this way, the charging process of the battery202 can be controlled at the terminal side, thus ensuring the safety andreliability of charging to battery 202.

As illustrated in FIG. 14, the terminal 2 further includes acommunication unit 205. The communication unit 205 is configured toestablish a bidirectional communication between the controller 204 andthe control unit 107 via the second charging interface 201 and the firstcharging interface 105. In other words, the terminal 2 and the poweradapter 1 can perform the bidirectional communication via the data wirein the USB interface. The terminal 2 supports the first charging modeand the second charging mode. The charging current of the secondcharging mode is greater than that of the first charging mode. Thecommunication unit 205 performs the bidirectional communication with thecontrol unit 107 such that the power adapter 1 determines to charge theterminal 2 in the second charging mode, and the control unit 107controls the power adapter 1 to output according to the charging currentcorresponding to the second charging mode, for charging the battery 202in the terminal 2.

In embodiments of the present disclosure, the power adapter 1 does notincrease the output current blindly for the second charging, but needsto perform the bidirectional communication with the terminal 2 tonegotiate whether to adopt the second charging mode. In contrast to therelated art, the safety of the second charging process is improved.

As an embodiment, the controller is configured to receive the firstinstruction sent by the control unit via the communication unit. Thefirst instruction is configured to query the terminal whether to operatein the second charging mode. The controller is configured to send afirst reply instruction to the control unit via the communication unit.The first reply instruction is configured to indicate that the terminalagrees to operate in the second charging mode.

As an embodiment, before the controller receives the first instructionsent by the control unit via the communication unit, the battery in theterminal is charged by the power adapter in the first charging mode.When the control unit determines that a charging duration of the firstcharging mode is greater than a predetermined threshold, the controlunit sends the first instruction to the communication unit in theterminal, and the controller receives the first instruction sent by thecontrol unit via the communication unit.

As an embodiment, before the power adapter outputs according to thecharging current corresponding to the second charging mode for chargingthe battery in the terminal, the controller is configured to perform thebidirectional communication with the control unit via the communicationunit, such that the power adapter determines the charging voltagecorresponding to the second charging mode.

As an embodiment, the controller is configured to receive a secondinstruction sent by the control unit, and to send a second replyinstruction to the control unit. The second instruction is configured toquery whether a current output voltage of the power adapter is suitablefor being used as the charging voltage corresponding to the secondcharging mode. The second reply instruction is configured to indicatethat the current output voltage of the power adapter is suitable, highor low.

As an embodiment, the controller is configured to perform thebidirectional communication with the control unit, such that the poweradapter determines the charging current corresponding to the secondcharging mode.

The controller is configured to receive a third instruction sent by thecontrol unit, in which the third instruction is configured to query amaximum charging current supported by the terminal. The controller isconfigured to send a third reply instruction to the control unit, inwhich the third reply instruction is configured to indicate the maximumcharging current supported by the terminal, such that the power adapterdetermines the charging current corresponding to the second chargingmode according to the maximum charging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the controller is configured toperform the bidirectional communication with the control unit, such thatthe power adapter continuously adjusts a charging current outputted tothe battery.

The controller is configured to receive a fourth instruction sent by thecontrol unit, in which the fourth instruction is configured to query acurrent voltage of the battery in the terminal. The controller isconfigured to send a fourth reply instruction to the control unit, inwhich the fourth reply instruction is configured to indicate the currentvoltage of the battery in the terminal, such that the power adaptercontinuously adjusts the charging current outputted to the batteryaccording to the current voltage of the battery.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the controller is configured toperform the bidirectional communication with the control unit via thecommunication unit, such that the power adapter determines whether thereis a poor contact between the first charging interface and the secondcharging interface.

The controller receives a fourth instruction sent by the control unit.The fourth instruction is configured to query a current voltage of thebattery in the terminal. The controller sends a fourth reply instructionto the control unit, in which the fourth reply instruction is configuredto indicate the current voltage of the battery in the terminal, suchthat the control unit determines whether there is the poor contactbetween the first charging interface and the second charging interfaceaccording to an output voltage of the power adapter and the currentvoltage of the battery.

As an embodiment, the controller is configured to receive a fifthinstruction sent by the control unit. The fifth instruction isconfigured to indicate that there is the poor contact between the firstcharging interface and the second charging interface.

In order to initiate and adopt the second charging mode, the poweradapter may perform a second charging communication procedure with theterminal, for example, by one or more handshakes, so as to realize thesecond charging of battery. Referring to FIG. 6, the second chargingcommunication procedure according to embodiments of the presentdisclosure and respective stages in the second charging process will bedescribed in detail. It should be understood that, communication actionsor operations illustrated in FIG. 6 are merely exemplary. Otheroperations or various modifications of respective operations in FIG. 6can be implemented in embodiments of the present disclosure. Inaddition, respective stages in FIG. 6 may be executed in an orderdifferent from that illustrated in FIG. 6, and it is unnecessary toexecute all the operations illustrated in FIG. 6. A curve in FIG. 6represents a variation trend of a peak value or a mean value of thecharging current, rather than a curve of actual charging current.

As illustrated in FIG. 6, the second charging process may include thefollowing five stages.

Stage 1:

After being coupled to a power supply providing device, the terminal maydetect a type of the power supply providing device via the data wire D+and D−. When detecting that the power supply providing device is a poweradapter, the terminal may absorb current greater than a predeterminedcurrent threshold I2, such as 1 A. When the power adapter detects thatcurrent outputted by the power adapter is greater than or equal to I2within a predetermined time period (such as a continuous time periodT1), the power adapter determines that the terminal has completed therecognition of the type of the power supply providing device. The poweradapter initiates a handshake communication between the power adapterand the terminal, and sends an instruction 1 (corresponding to theabove-mentioned first instruction) to query the terminal whether tooperate in the second charging mode (or flash charging).

When receiving a reply instruction indicating that the terminaldisagrees to operate in the second charging mode from the terminal, thepower adapter detects the output current of the power adapter again.When the output current of the power adapter is still greater than orequal to I2 within a predetermined continuous time period (such as acontinuous time period T1), the power adapter initiates a request againto query the terminal whether to operate in the second charging model.The above actions in stage 1 are repeated, until the terminal repliesthat it agrees to operate in the second charging mode or the outputcurrent of the power adapter is no longer greater than or equal to I2.

After the terminal agrees to operate in the second charging mode, thesecond charging process is initiated, and the second chargingcommunication procedure goes into stage 2.

Stage 2:

For the voltage with the steamed bun waveform outputted by the poweradapter, there may be several levels. The power adapter sends aninstruction 2 (corresponding to the above-mentioned second instruction)to the terminal to query the terminal whether the output voltage of thepower adapter matches to the current voltage of the battery (or whetherthe output voltage of the power adapter is suitable, i.e., suitable forthe charging voltage in the second charging mode), i.e., whether theoutput voltage of the power adapter meets the charging requirement.

The terminal replies that the output voltage of the power adapter ishigher, lower or suitable. When the power adapter receives a feedbackindicating that the output voltage of the power adapter is lower orhigher from the terminal, the control unit adjusts the output voltage ofthe power adapter by one level by adjusting the duty ratio of the PWMsignal, and sends the instruction 2 to the terminal again to query theterminal whether the output voltage of the power adapter matches.

The above actions in stage 2 are repeated, until the terminal replies tothe power adapter that the output voltage of the power adapter is at amatching level. And then the second charging communication proceduregoes into stage 3.

Stage 3:

After the power adapter receives the feedback indicating that the outputvoltage of the power adapter matches from the terminal, the poweradapter sends an instruction 3 (corresponding to the above-mentionedthird instruction) to the terminal to query the maximum charging currentsupported by the terminal. The terminal returns to the power adapter themaximum charging current supported by itself, and then the secondcharging communication procedure goes into stage 4.

Stage 4:

After receiving a feedback indicating the maximum charging currentsupported by the terminal from the terminal, the power adapter may setan output current reference value. The control unit 107 adjusts the dutyratio of the PWM signal according to the output current reference value,such that the output current of the power adapter meets the chargingcurrent requirement of the terminal, and the second chargingcommunication procedure goes into constant current charging stage. Theconstant current charging stage means that the peak value or mean valueof the output current of the power adapter basically remains unchanged(which means that the variation amplitude of the peak value or meanvalue of the output current is very small, for example within a range of5% of the peak value or mean value of the output current), namely, thepeak value of the current with the third ripple waveform keeps constantin each period.

Stage 5:

When the second charging communication procedure goes into the constantcurrent stage, the power adapter sends an instruction 4 (correspondingto the above-mentioned fourth instruction) at intervals to query thecurrent voltage of battery in the terminal. The terminal may feedback tothe power adapter the current voltage of the battery, and the poweradapter may determine according to the feedback of the current voltageof the battery whether there is a poor USB contact (i.e., a poor contactbetween the first charging interface and the second charging interface)and whether it is necessary to decrease the charging current value ofthe terminal. When the power adapter determines that there is the poorUSB contact, the power adapter sends an instruction 5 (corresponding tothe above-mentioned fifth instruction), and then the power adapter isreset, such that the second charging communication procedure goes intostage 1 again.

In some embodiments of the present disclosure, in stage 1, when theterminal replies to the instruction 1, data corresponding to theinstruction 1 may carry data (or information) on the path impedance ofthe terminal The data on the path impedance of the terminal may be usedin stage 5 to determine whether there is the poor USB contact.

In some embodiments of the present disclosure, in stage 2, the timeperiod from when the terminal agrees to operate in the second chargingmode to when the power adapter adjusts the voltage to a suitable valuemay be limited in a certain range. If the time period exceeds apredetermined range, the terminal may determine that there is anexception request, thus a quick reset is performed.

In some embodiments of the present disclosure, in stage 2, the terminalmay give a feedback indicating that the output voltage of the poweradapter is suitable/matches to the power adapter when the output voltageof the power adapter is adjusted to a value higher than the currentvoltage of the battery by ΔV (ΔV is about 200-500 mV). When the terminalgives a feedback indicating that the output voltage of the power adapteris not suitable (higher or lower) to the power adapter, the control unit107 adjusts the duty ratio of the PWM signal according to the voltagesampling value, so as to adjust the output voltage of the power adapter.

In some embodiments of the present disclosure, in stage 4, the adjustingspeed of the output current value of the power adapter may be controlledto be in a certain range, thus avoiding an abnormal interruption of thesecond charging due to the too fast adjusting speed.

In some embodiments of the present disclosure, in stage 5, the variationamplitude of the output current value of the power adapter may becontrolled to be within 5%, i.e., stage 5 may be regarded as theconstant current stage.

In some embodiments of the present disclosure, in stage 5, the poweradapter monitors the impedance of a charging loop in real time, i.e.,the power adapter monitors the impedance of the whole charging loop bymeasuring the output voltage of the power adapter, the charging currentand the read-out voltage of the battery in the terminal. When theimpedance of the charging loop>the path impedance of the terminal+theimpedance of the second charging data wire, it may be considered thatthere is the poor USB contact, and thus a second charging reset isperformed.

In some embodiments of the present disclosure, after the second chargingmode is started, a time interval of communications between the poweradapter and the terminal may be controlled to be in a certain range,such that the second charging reset can be avoided.

In some embodiments of the present disclosure, the termination of thesecond charging mode (or the second charging process) may be arecoverable termination or an unrecoverable termination.

For example, when the terminal detects that the battery is fully chargedor there is the poor USB contact, the second charging is stopped andreset, and the second charging communication procedure goes into stage1. When the terminal disagrees to operate in the second charging mode,the second charging communication procedure would not go into stage 2,thus the termination of the second charging process may be considered asan unrecoverable termination.

For another example, when an exception occurs in the communicationbetween the terminal and the power adapter, the second charging isstopped and reset, and the second charging communication procedure goesinto stage 1. After requirements for stage 1 are met, the terminalagrees to operate in the second charging mode to recover the secondcharging process, thus the termination of the second charging processmay be considered as a recoverable termination.

For another example, when the terminal detects an exception occurring inthe battery, the second charging is stopped and reset, and the secondcharging communication procedure goes into stage 1. After the secondcharging communication procedure goes into stage 1, the terminaldisagrees to operate in the second charging mode. Till the batteryreturns to normal and the requirements for stage 1 are met, the terminalagrees to operate in the second charging to recover the second chargingprocess. Thus, the termination of second charging process may beconsidered as a recoverable termination.

Communication actions or operations illustrated in FIG. 6 are merelyexemplary. For example, in stage 1, after the terminal is coupled to thepower adapter, the handshake communication between the terminal and thepower adapter may be initiated by the terminal. In other words, theterminal sends an instruction 1 to query the power adapter whether tooperate in the second charging mode (or flash charging). When receivinga reply instruction indicating that the power adapter agrees to operatein the second charging mode from the power adapter, the terminaloperates in the second charging process.

Communication actions or operations illustrated in FIG. 6 are merelyexemplary. For example, after stage 5, there is a constant voltagecharging stage. In other words, in stage 5, the terminal may feedbackthe current voltage of the battery in the terminal to the power adapter.As the voltage of the battery increases continuously, the charging goesinto the constant voltage charging stage when the current voltage of thebattery reaches a constant voltage charging voltage threshold. Thecontrol unit 107 adjusts the duty ratio of the PWM signal according tothe voltage reference value (i.e., the constant voltage charging voltagethreshold), such that the output voltage of the power adapter meets thecharging voltage requirement of the terminal, i.e., the output voltageof the power adapter basically changes at a constant rate. During theconstant voltage charging stage, the charging current decreasesgradually. When the current reduces to a certain threshold, the chargingis stopped and it is illustrated that the battery is fully charged. Theconstant voltage charging refers to that the peak voltage with the thirdripple waveform basically keeps constant.

In embodiments of the present disclosure, acquiring output voltage ofthe power adapter means that the peak value or mean value of voltagewith the third ripple waveform is acquired. Acquiring output current ofthe power adapter means that the peak value or mean value of currentwith the third ripple waveform is acquired.

In an embodiment of the present disclosure, as illustrated in FIG. 7,the power adapter 1 further includes a controllable switch 108 and afiltering unit 109 in series. The controllable switch 108 and thefiltering unit 109 in series are coupled to the first output end of thesecond rectifier 104. The control unit 107 is further configured tocontrol the controllable switch 108 to switch on when determining thecharging mode as the first charging mode, and to control thecontrollable switch 108 to switch off when determining the charging modeas the second charging mode. The output end of the second rectifier 104is further coupled to one or more groups of small capacitors inparallel, which can not only realize a noise reduction, but also reducethe occurrence of surge phenomenon. The output end of the secondrectifier 104 is further coupled to an LC filtering circuit or 7E typefiltering circuit, so as to filter out ripple interference. Asillustrated in FIG. 7B, the output end of the second rectifier 104 iscoupled to an LC filtering circuit. It should be noted that, allcapacitors in the LC filtering circuit or the 7E type filtering circuitare small capacitors, which occupy small space.

The filtering unit 109 includes a filtering capacitor, which supports astandard charging of 5V corresponding to the first charging mode. Thecontrollable switch 108 may be formed of a semiconductor switch elementsuch as a MOS transistor. When the power adapter charges the battery inthe terminal in the first charging mode (or called as standardcharging), the control unit 107 controls the controllable switch 108 toswitch on so as to incorporate the filtering unit 109 into the circuit,such that a filtering can be performed on the output of the secondrectifier 104. In this way, the direct charging technology iscompatible, i.e., the direct current is applied to the battery in theterminal so as to realize direct current charging of the battery. Forexample, in general, the filtering unit includes an electrolyticcondenser and a common capacitor such as a small capacitor supportingstandard charging of 5V (for example, a solid-state capacitor) inparallel. Since the electrolytic condenser occupies a bigger volume, inorder to reduce the size of the power adapter, the electrolyticcondenser may be removed from the power adapter and only one capacitorwith low capacitance is left. When the first charging mode is adopted, abranch where the small capacitor is located is switched on, and thecurrent is filtered to realize a stable output with low power forperforming a direct current charging on the battery. When the secondcharging mode is adopted, a branch where the small capacitor is locatedis switched off, and the output of the second rectifier 104 directlyapply the voltage/current with ripple waveform without filtering to thebattery, so as to realize a second charging of the battery.

According to an embodiment of the present disclosure, the control unit107 is further configured to obtain the charging current and/or thecharging voltage corresponding to the second charging mode according tothe status information of the terminal and to adjust the duty ratio ofthe control signal such as the PWM signal according to the chargingcurrent and/or the charging voltage corresponding to the second chargingmode, when determining the charging mode as the second charging mode. Inother words, when determining the current charging mode as the secondcharging mode, the control unit 107 obtains the charging current and/orthe charging voltage corresponding to the second charging mode accordingto the obtained status information of the terminal such as the voltage,the electric quantity and the temperature of the battery, runningparameters of the terminal and power consumption information ofapplications running on the terminal, and adjusts the duty ratio of thecontrol signal according to the charging current and/or the chargingvoltage, such that the output of the power adapter meets the chargingrequirement, thus realizing the second charging of the battery.

The status information of the terminal includes the temperature of theterminal. When the temperature of the battery is greater than a firstpredetermined temperature threshold, or the temperature of the batteryis less than a second predetermined temperature threshold, if thecurrent charging mode is the second charging mode, the second chargingmode is switched to the first charging mode. The first predeterminedtemperature threshold is greater than the second predeterminedtemperature threshold. In other words, when the temperature of thebattery is too low (for example, corresponding to less than the secondpredetermined temperature threshold) or too high (for example,corresponding to greater than the first predetermined temperaturethreshold), it is unsuitable to perform the second charging, such thatit needs to switch from the second charging mode to the first chargingmode. In embodiments of the present disclosure, the first predeterminedtemperature threshold and the second predetermined temperature thresholdcan be set according to actual situations, or can be written into thestorage of the control unit (such as the MCU of the power adapter).

In an embodiment of the present disclosure, the control unit 107 isfurther configured to control the switch unit 102 to switch off when thetemperature of the battery is greater than a predetermined hightemperature protection threshold. Namely, when the temperature of thebattery exceeds the high temperature protection threshold, the controlunit 107 needs to apply a high temperature protection strategy tocontrol the switch unit 102 to switch off, such that the power adapterstops charging the battery, thus realizing the high protection of thebattery and improving the safety of charging. The high temperatureprotection threshold may be different from or the same to the firsttemperature threshold. In an embodiment, the high temperature protectionthreshold is greater than the first temperature threshold.

In another embodiment of the present disclosure, the controller isfurther configured to obtain the temperature of the battery, and tocontrol the charging control switch to switch off (i.e., the chargingcontrol switch can be switched off at the terminal side) when thetemperature of the battery is greater than the predetermined hightemperature protection threshold, so as to stop the charging process ofthe battery and to ensure the safety of charging.

Moreover, in an embodiment of the present disclosure, the control unitis further configured to obtain a temperature of the first charginginterface, and to control the switch unit to switch off when thetemperature of the first charging interface is greater than apredetermined protection temperature. In other words, when thetemperature of the charging interface exceeds a certain temperature, thecontrol unit 107 needs to apply the high temperature protection strategyto control the switch unit 102 to switch off, such that the poweradapter stops charging the battery, thus realizing the high protectionof the battery and improving the safety of charging.

Certainly, in another embodiment of the present disclosure, thecontroller obtains the temperature of the first charging interface byperforming the bidirectional communication with the control unit. Whenthe temperature of the first charging interface is greater than thepredetermined protection temperature, the controller controls thecharging control switch to switch off (see FIG. 13 and FIG. 14), i.e.,switches off the charging control switch at the terminal side, so as tostop the charging process of the battery, thus ensuring the safety ofcharging.

In detail, in an embodiment of the present disclosure, as illustrated inFIG. 8, the power adapter 1 further includes a driving unit 110 such asa MOSFET driver. The driving unit 110 is coupled between the switch unit102 and the control unit 107. The driving unit 110 is configured todrive the switch unit 102 to switch on or off according to the controlsignal. Certainly, it should be noted, in other embodiments of thepresent disclosure, the driving unit 110 may also be integrated in thecontrol unit 107.

Further, as illustrated in FIG. 8, the power adapter 1 further includesan isolation unit 111. The isolation unit 111 is coupled between thedriving unit 110 and the control unit 107, to prevent high voltages fromaffecting the control unit 107 at the secondary side of the transformer103, i.e. realize a high-voltage isolation between the primary side andthe secondary side of the power adapter 1 (or a high-voltage isolationbetween the primary winding and the secondary winding of the transformer103). The isolation unit 111 may be implemented in an optocouplerisolation manner, or in other isolation manners. By setting theisolation unit 111, the control unit 107 may be disposed at thesecondary side of the power adapter 1 (or the secondary winding side ofthe transformer 103), such that it is convenient to communicate with theterminal 2, and the space design of the power adapter 1 becomes easierand simpler.

Certainly, it should be understood that, in other embodiments of thepresent disclosure, both the control unit 107 and the driving unit 110can be disposed as the primary side, in this way, an isolation unit suchas the isolation unit 111 can be disposed between the control unit 107and the sampling unit 106, so as to prevent high voltages from affectingthe control unit 107 at the secondary side of the transformer 103, i.e.realize the high-voltage isolation between the primary side and thesecondary side of the power adapter 1.

Further, in embodiments of the present disclosure, when the control unit107 is disposed at the secondary side, the isolation unit 111 isrequired, and the isolation unit 111 may be integrated in the controlunit 107. In other words, when the signal is transmitted from theprimary side to the secondary side or from the secondary side to theprimary side, the isolation unit 111 is required to prevent highvoltages from affecting the control unit 107 at the secondary side ofthe transformer 103, i.e. realize the high-voltage isolation.

In an embodiment of the present disclosure, as illustrated in FIG. 9,the power adapter 1 further includes an auxiliary winding and a powersupply unit 112. The auxiliary winding generates a fourth voltage with afourth ripple waveform according to the modulated first voltage. Thepower supply unit 112 is coupled to the auxiliary winding. The powersupply unit 112 (for example, including a filtering voltage regulatormodule, a voltage converting module and the like) is configured toconvert the fourth voltage with the fourth ripple waveform and output adirect current, and to supply power to the driving unit 110 and/or thecontrol unit 107 respectively. The power supply unit 112 may be formedof a small filtering capacitor, a voltage regulator chip or otherelements, performs a process and conversation on the fourth voltage withthe fourth ripple waveform and outputs the low voltage direct currentsuch as 3.3V, 5V or the like.

In other words, the power supply of the driving unit 110 can be obtainedby performing a voltage conversation on the fourth voltage with thefourth ripple waveform by the power supply unit 112. When the controlunit 107 is disposed at the primary side, the power supply of thecontrol unit 107 can also be obtained by performing a voltageconversation on the fourth voltage with the fourth ripple waveform bythe power supply unit 112. As illustrated in FIG. 9, when the controlunit 107 is disposed at the primary side, the power supply unit 112provides two lines of direct current outputs, so as to supply power tothe driving unit 110 and the control unit 107 respectively. Anoptocoupler isolation unit 111 is arranged between the control unit 107and the sampling unit 106 so as to prevent high voltages from affectingthe control unit 107 at the secondary side of the transformer 103, i.e.realize the high-voltage isolation between the primary side and thesecondary side of the power adapter 1.

When the control unit 107 is disposed at the primary side and integratedwith the driving unit 110, the power supply unit 112 supplies power tothe control unit 107 only. When the control unit 107 is disposed at thesecondary side and the driving unit 110 is disposed at the primary side,the power supply unit 112 supplies power to the driving unit 110 only.The power supply to the control unit 107 is realized by the secondaryside, for example, a power supply unit converts the third voltage withthe third ripple waveform outputted by the second rectifier 104 todirect current to supply power to the control unit 107.

Moreover, in embodiments of the present disclosure, several smallcapacitors are coupled in parallel to the output end of first rectifier101 for filtering. Or the output end of the first rectifier 110 iscoupled to an LC filtering circuit.

In another embodiment of the present disclosure, as illustrated in FIG.10, the power adapter 1 further includes a first voltage detecting unit113. The first voltage detecting unit 113 is coupled to the auxiliarywinding and the control unit 107 respectively. The first voltagedetecting unit 113 is configured to detect the fourth voltage togenerate a voltage detecting value. The control unit 107 is furtherconfigured to adjust the duty ratio of the control signal according tothe voltage detecting value.

In other words, the control unit 107 may reflect the voltage outputtedby the second rectifier 104 with the voltage outputted by the secondarywinding and detected by the first voltage detecting unit 113, and thenadjusts the duty ratio of the control signal according to the voltagedetecting value, such that the output of the second rectifier 104 meetsthe charging requirement of the battery.

In detail, in an embodiment of the present disclosure, as illustrated inFIG. 11, the sampling unit 106 includes a first current sampling circuit1061 and a first voltage sampling circuit 1062. The first currentsampling circuit 1061 is configured to sample the current outputted bythe second rectifier 104 so as to obtain the current sampling value. Thefirst voltage sampling circuit 1062 is configured to sample the voltageoutputted by the second rectifier 104 so as to obtain the voltagesampling value.

In an embodiment of the present disclosure, the first current samplingcircuit 1061 can sample the current outputted by the second rectifier104 by sampling voltage on a resistor (current detection resistor)coupled to the first output end of the second rectifier 104. The firstvoltage sampling circuit 1062 can sample the voltage outputted by thesecond rectifier 104 by sampling the voltage cross the first output endand the second output end of the second rectifier 104.

Moreover, in an embodiment of the present disclosure, as illustrated inFIG. 11, the first voltage sampling circuit 1062 includes a peak voltagesampling and holding unit, a cross-zero sampling unit, a leakage unitand an AD sampling unit. The peak voltage sampling and holding unit isconfigured to sample and hold a peak voltage of the third voltage. Thecross-zero sampling unit is configured to sample a zero crossing pointof the third voltage. The leakage unit is configured to perform aleakage on the peak voltage sampling and holding unit at the zerocrossing point. The AD sampling unit is configured to sample the peakvoltage in the peak voltage sampling and holding unit so as to obtainthe voltage sampling value.

By providing with the peak voltage sampling and holding unit, thecross-zero sampling unit, the leakage unit and the AD sampling unit inthe first voltage sampling circuit 1062, the voltage outputted by thesecond rectifier 104 may be sampled accurately, and it can be guaranteedthat the voltage sampling value keeps synchronous with the firstvoltage, i.e., the phase and variation trend of magnitude of the voltagesampling value are consistent with those of the first voltagerespectively.

According to an embodiment of the present disclosure, as illustrated inFIG. 12, the power adapter 1 further includes a second voltage samplingcircuit 114. The second voltage sampling circuit 114 is configured tosample the first voltage with the first ripple waveform. The secondvoltage sampling circuit 114 is coupled to the control unit 107. Whenthe voltage value sampled by the second voltage sampling circuit 114 isgreater than a first predetermined voltage value, the control unit 104controls the switch unit 102 to switch on for a predetermined timeperiod, for performing a discharge on the surge voltage, spike voltagein the first voltage with the first ripple waveform.

As illustrated in FIG. 12, the second voltage sampling circuit 114 canbe coupled to the first output end and the second output end of thefirst rectifier 101, so as to sample the first voltage with the firstripple waveform. The control unit 107 performs a determination on thevoltage value sampled by the second voltage sampling circuit 114. Whenthe voltage value sampled by the second voltage sampling circuit 114 isgreater than the first predetermined voltage value, it indicates thatthe power adapter 1 is disturbed by lightning stroke and the surgevoltage is generated. At this time, a leakage is required for the surgevoltage to ensure the safety and reliability of charging. The controlunit 107 controls the switch unit 102 to switch on for a certain timeperiod, to form a leakage circuit, such that the leakage is performed onthe surge voltage caused by lightning stroke, thus avoiding thedisturbance caused by the lightning stroke when the power adaptercharges the terminal, and effectively improving the safety andreliability of the charging of the terminal. The first predeterminedvoltage value may be determined according to actual situations.

In an embodiment of the present disclosure, during a process that thepower adapter 1 charges the battery 202 of the terminal 2, the controlunit 107 is further configured to control the switch unit 102 to switchoff when the voltage sampling value sampled by the sampling unit 106 isgreater than a second predetermined voltage value. Namely, the controlunit 107 further performs a determination on the voltage sampling valuesampled by the sampling unit 106. When the voltage sampling valuesampled by the sampling unit 106 is greater than the secondpredetermined voltage value, it indicates that the voltage outputted bythe power adapter 1 is too high. At this time, the control unit 107controls the power adapter to stop charging the battery 202 of theterminal 2 by controlling the switch unit 102 to switch off. In otherwords, the control unit 107 realizes the over-voltage protection of thepower adapter 1 by controlling the switch unit 102 to switch off, thusensuring the safety of charging.

Certainly, in an embodiment of the present disclosure, the controller204 obtains the voltage sampling value sampled by the sampling unit 106by performing a bidirectional communication with the control unit 107(see in FIG. 13 and FIG. 14), and controls the charging control switch203 to switch off when the voltage sampling value sampled by thesampling unit 106 is greater than the second predetermined voltagevalue. Namely, the charging control switch 203 is controlled to switchoff at the terminal side, so as to stop the charging process of thebattery 202, such that the safety of charging the battery 202 can beensured.

Further, the control unit 107 is further configured to control theswitch unit 102 to switch off when the current sampling value sampled bythe sampling unit 106 is greater than a predetermined current value. Inother words, the control unit 107 further performs a determination onthe current sampling value sampled by the sampling unit 106. When thecurrent sampling value sampled by the sampling unit 106 is greater thanthe predetermined current value, it indicates that the current outputtedby the power adapter 1 is too high. At this time, the control unit 107controls the power adapter 1 to stop charging the terminal bycontrolling the switch unit 102 to switch off. In other words, thecontrol unit 107 realizes the over-current protection of the poweradapter 1 by controlling the switch unit 102 to switch off, thusensuring the safety of charging.

Similarly, the controller 204 obtains the current sampling value sampledby the sampling unit 106 by performing the bidirectional communicationwith the control unit 107 (see FIG. 13 and FIG. 14), and controls toswitch off the charging control switch 203 when the current samplingvalue sampled by the sampling unit 106 is greater than the predeterminedcurrent value. In other words, the charging control switch 203 iscontrolled to be switched off at the terminal side, so as to stop thecharging process of the battery 202, thus ensuring the safety ofcharging.

The second predetermined voltage value and the predetermined currentvalue may be set or written into a storage of the control unit (forexample, the control unit 107 of the power adapter 1, such as the MCU ofthe power adapter) according to actual situations.

In embodiments of the present disclosure, the terminal may be a mobileterminal, such as a mobile phone, a mobile power supply such as a powerbank, a multimedia player, a notebook PC, a wearable device or the like.

With the charging system according to embodiments of the presentdisclosure, the power adapter is controlled to output the third voltagewith the third ripple waveform, and the third voltage with the thirdripple waveform outputted by the power adapter is directly applied tothe battery of the terminal, thus realizing second charging to thebattery directly by the ripple output voltage/current. In contrast tothe constant voltage and constant current, a magnitude of the rippleoutput voltage/current changes periodically, such that a lithiumprecipitation of the lithium battery may be reduced, the service life ofthe battery may be improved, and a probability and intensity of arcdischarge of a contact of a charging interface may be reduced, theservice life of the charging interface may be prolonged, and it isbeneficial to reduce polarization effect of the battery, improvecharging speed, and decrease heat emitted by the battery, thus ensuringa reliability and safety of the terminal during the charging. Moreover,since the power adapter outputs the voltage with the ripple waveform, itis unnecessary to provide an electrolytic condenser in the poweradapter, which not only realizes simplification and miniaturization ofthe power adapter, but also decreases cost greatly.

Embodiments of the present disclosure further provide a power adapter.The power adapter includes a first rectifier, a switch unit, atransformer, a second rectifier, a sampling unit and a control unit. Thefirst rectifier is configured to rectify an input alternating currentand output a first voltage with a first ripple waveform. The switch unitis configured to modulate the first voltage according to a controlsignal and output a modulated first voltage. The transformer isconfigured to output a second voltage with a second ripple waveformaccording to the modulated first voltage. The second rectifier isconfigured to rectify the second voltage to output a third voltage witha third ripple waveform, in which the third voltage is configured to beintroduced into a terminal to charge a battery in the terminal when thepower adapter is coupled to the terminal. The sampling unit isconfigured to sample current outputted by the second rectifier to obtaina current sampling value. The control unit is coupled to the samplingunit and the switch unit respectively, and configured to output thecontrol signal to the switch unit, and to control a charging processperformed by the power adapter on a terminal to be in a constant currentcharging stage by adjusting a duty ratio of the control signal when itis determined that current outputted by the power adapter is high or lowaccording to the current sampling value.

In an embodiment, the power adapter further includes a first charginginterface. The first charging interface is coupled to the secondrectifier, configured to apply the third voltage to a battery in aterminal via a second charging interface of the terminal when the firstcharging interface is coupled to the second charging interface, in whichthe second charging interface is coupled to the battery.

With the power adapter according to embodiments of the presentdisclosure, the third voltage with the third ripple waveform isoutputted via the first charging interface, and the third voltage isdirectly applied to the battery of the terminal via the second charginginterface of the terminal, thus realizing second charging to the batterydirectly by the ripple output voltage/current. In contrast to theconventional constant voltage and constant current, a magnitude of theripple output voltage/current changes periodically, such that a lithiumprecipitation of the lithium battery may be reduced, the service life ofthe battery may be improved, and a probability and intensity of arcdischarge of a contact of a charging interface may be reduced, theservice life of the charging interface may be prolonged, and it isbeneficial to reduce polarization effect of the battery, improvecharging speed, and decrease heat emitted by the battery, thus ensuringa reliability and safety of the terminal during the charging. Moreover,since the voltage with the ripple waveform is output, it is unnecessaryto provide an electrolytic condenser, which not only realizessimplification and miniaturization of the power adapter, but alsodecreases cost greatly.

FIG. 15 is a flow chart of a charging method according to embodiments ofthe present disclosure. As illustrated in FIG. 15, the charging methodincludes the followings.

At block S1, when a power adapter is coupled to a terminal, a firstrectification is performed on alternating current inputted into thepower adapter to output a first voltage with a first ripple waveform.

In other words, a first rectifier in the power adapter rectifies theinputted alternating current (i.e., the mains supply, such asalternating current of 220V, 50 Hz or 60 Hz) and outputs the firstvoltage (for example, 100 Hz or 120 Hz) with the first ripple waveform,such as a voltage with a steamed bun waveform.

At block S2, the first voltage with the first ripple waveform ismodulated by a switch unit, and then is converted by a transformer toobtain a second voltage with a second ripple waveform.

The switch unit may be formed of a MOS transistor. A PWM control isperformed on the MOS transistor to perform a chopping modulation on thevoltage with the steamed bun waveform. And then, the modulated firstvoltage is coupled to a secondary side by the transformer, such that thesecondary winding outputs the second voltage with the second ripplewaveform.

In an embodiment of the present disclosure, a high-frequency transformeris used for conversion, such that the size of the transformer is small,thus realizing miniaturization of the power adapter with high-power.

At block S3, a second rectification is performed on the second voltagewith the second ripple waveform to output a third voltage with a thirdripple waveform. The third voltage with the third ripple waveform may beapplied to a battery of the terminal via the second charging interface,so as to charge the battery of the terminal.

In an embodiment of the present disclosure, the second rectification isperformed by a second rectifier on the second voltage with the secondripple waveform. The second rectifier may be formed of a diode or a MOStransistor, and can realize a secondary synchronous rectification, suchthat the third ripple waveform keeps synchronous with the waveform ofthe modulated first voltage.

At block S4, current after the second rectification is sampled to obtaina current sampling value.

At block S5, a charging process performed by the power adapter on theterminal is controlled to be in a constant current charging stage byadjusting a duty ratio of a control signal for controlling the switchunit when it is determined that current outputted by the power adapteris high or low according to the current sampling value.

In an embodiment, when the current outputted by the power adapter ishigh or low, a peak current/a mean current of the third ripple waveformoutputted by the second rectifier is higher or lower than a currentreference value of the constant current charging stage, i.e. higher orlower than the current reference value of the constant current chargingstage by a certain preset value.

In an embodiment of the present disclosure, the duty ratio of thecontrol signal is reduced when the current outputted by the poweradapter is high, such that the current outputted by the power adapter isreduced to the current reference value. The duty ratio of the controlsignal is increased when the current outputted by the power adapter islow, such that the current outputted by the power adapter is increasedto the current reference value.

In an embodiment of the present disclosure, the above charging methodfurther includes: sampling voltage after the second rectification toobtain a voltage sampling value; and after the constant current stage iscompleted, controlling the charging process performed by the poweradapter on the terminal to be in a constant voltage charging stage byadjusting the duty ratio of the control signal when it is determinedthat that voltage outputted by the power adapter is high or lowaccording to the voltage sampling value.

In an embodiment, when the voltage outputted by the power adapter ishigh or low, a peak voltage/a mean voltage of the third ripple waveformoutputted by the second rectifier is higher or lower than a voltagereference value of the constant voltage charging stage, i.e. is higheror lower than the voltage reference value of the constant voltagecharging stage by a certain preset value.

In an embodiment of the present disclosure, the duty ratio of thecontrol signal is reduced when the voltage outputted by the poweradapter is high, such that the voltage outputted by the power adapter isreduced to the voltage reference value. The duty ratio of the controlsignal is increased when the voltage outputted by the power adapter islow, such that the voltage outputted by the power adapter is increasedto the voltage reference value.

Further, in an embodiment of the present disclosure, the duty radio ofthe control signal is adjusted so as to make the third voltage with thethird ripple waveform meet the charging requirement.

In an embodiment, the third voltage with the third ripple waveformmeeting the charging requirement means that, the third voltage andcurrent with the third ripple waveform need to meet the charging voltageand charging current when the battery is charged. In other words, theduty ratio of the control signal (such as a PWM signal) is adjustedaccording to the sampled voltage and/or current outputted by the poweradapter, so as to adjust the output of the power adapter in real timeand realize a closed-loop adjusting control, such that the third voltagewith the third ripple waveform meets the charging requirement of theterminal, thus ensuring the stable and safe charging of the battery. Indetail, a waveform of a charging voltage outputted to a battery isillustrated in FIG. 3, in which the waveform of the charging voltage isadjusted according to the duty ratio of the PWM signal. A waveform of acharging current outputted to a battery is illustrated in FIG. 4, inwhich the waveform of the charging current is adjusted according to theduty ratio of the PWM signal.

In an embodiment of the present disclosure, by controlling the switchunit, a chopping modulation is directly performed on the first voltagewith the first ripple waveform i.e., the steamed bun waveform after afull-bridge rectification, and then a modulated voltage is sent to thehigh-frequency transformer and is coupled from the primary side to thesecondary side via the high-frequency transformer, and then is changedback to the voltage/current with the steamed bun waveform after asynchronous rectification. The voltage/current with the steamed bunwaveform is directly transmitted to the battery so as to realize secondcharging to the battery. The magnitude of the voltage with the steamedbun waveform may be adjusted according to the duty ratio of the PWMsignal, such that the output of the power adapter may meet the chargingrequirement of the battery. It can be seen from that, electrolyticcondensers at the primary side and the secondary side in the poweradapter can be removed, and the battery can be directly charged via thevoltage with the steamed bun waveform, such that a size of the poweradapter may be reduced, thus realizing miniaturization of the poweradapter, and decreasing cost greatly.

According to an embodiment of the present disclosure, a frequency of thecontrol signal is adjusted according to the voltage sampling valueand/or the current sampling value. That is, the output of the PWM signalto the switch unit is controlled to maintain for a continuous timeperiod, and then stop for a predetermined time period and then restart.In this way, the voltage applied to the battery is intermittent, thusrealizing the intermittent charging of the battery, which avoids asafety hazard caused by heating phenomenon occurring when the battery ischarged continuously and improves the reliability and safety of thecharging to the battery. The control signal outputted to the switch unitis illustrated in FIG. 5.

Further, the above charging method includes: performing a communicationwith the terminal via the first charging interface to obtain statusinformation of the terminal, and adjusting the duty ratio of the controlsignal according to the status information of the terminal, the voltagesampling value and/or current sampling value.

In other words, when the second charging interface is coupled to thefirst charging interface, the power adapter and the terminal may sendcommunication query instructions to each other, and a communicationconnection can be established between the power adapter and the terminalafter corresponding reply instructions are received, such that the poweradapter can obtain the status information of the terminal, negotiateswith the terminal about the charging mode and the charging parameter(such as the charging current, the charging voltage) and controls thecharging process.

According to an embodiment of the present disclosure, a fourth voltagewith a fourth ripple waveform can be generated by a conversion of thetransformer, and the fourth voltage with the fourth ripple waveform canbe detected to generate a voltage detecting value, and the duty ratio ofthe control signal can be adjusted according to the voltage detectingvalue.

In detail, the transformer can be provided with an auxiliary winding.The auxiliary winding can generate the fourth voltage with the fourthripple waveform according to the modulated first voltage. The outputvoltage of the power adapter can be reflected by detecting the fourthvoltage with the fourth ripple waveform, and the duty ratio of thecontrol signal can be adjusted according to the voltage detecting value,such that the output of the power adapter meets the charging requirementof the battery.

In an embodiment of the present disclosure, sampling voltage after thesecond rectification to obtain a voltage sampling value includes:sampling and holding a peak voltage of the voltage after the secondrectification, and sampling a zero crossing point of the voltage afterthe second rectification; performing a leakage on a peak voltagesampling and holding unit configured for sampling and holding the peakvoltage at the zero crossing point; and sampling the peak voltage in thepeak voltage sampling and holding unit so as to obtain the voltagesampling value. In this way, an accurate sampling can be performed onthe voltage outputted by the power adapter, and it can be guaranteedthat the voltage sampling value keeps synchronous with the first voltagewith the first ripple waveform, i.e., the phase and variation trend ofmagnitude of the voltage sampling value are consistent with those of thefirst voltage respectively.

Further, in an embodiment of the present disclosure, the above chargingmethod includes: sampling the first voltage with the first ripplewaveform, and controlling the switch unit to switch on for apredetermined time period for performing a discharge on surge voltage inthe first voltage with the first ripple waveform when a sampled voltagevalue is greater than a first predetermined voltage value.

The first voltage with the first ripple waveform is sampled so as todetermine the sampled voltage value. When the sampled voltage value isgreater than the first predetermined voltage value, it indicates thatthe power adapter is disturbed by lightning stroke and the surge voltageis generated. At this time, a leakage is required for the surge voltageto ensure the safety and reliability of charging. It is required tocontrol the switch unit to switch on for a certain time period, to forma leakage circuit, such that the leakage is performed on the surgevoltage caused by lightning stroke, thus avoiding the disturbance causedby the lightning stroke when the power adapter charges the terminal, andeffectively improving the safety and reliability of the charging of theterminal. The first predetermined voltage value may be determinedaccording to actual situations.

According an embodiment of the present disclosure, a communication withthe terminal is performed via the first charging interface to determinethe charging mode. When the charging mode is determined as the secondcharging mode, the charging current and/or charging voltagecorresponding to the second charging mode can be obtained according tothe status information of the terminal, so as to adjust the duty ratioof the control signal according to the charging current and/or chargingvoltage corresponding to the second charging mode. The charging modeincludes the second charging mode and the first charging mode.

In other words, when the current charging mode is determined as thesecond charging mode, the charging current and/or charging voltagecorresponding to the second charging mode can be obtained according tothe status information of the terminal, such as the voltage, electricquantity, temperature of the battery, running parameters of the terminaland power consumption information of applications running on theterminal or the like. And the duty ratio of the control signal isadjusted according to the obtained charging current and/or chargingvoltage, such that the output of the power adapter meets the chargingrequirement, thus realizing the second charging of the terminal.

The status information of the terminal includes the temperature of thebattery. When the temperature of the battery is greater than a firstpredetermined temperature threshold, or the temperature of the batteryis less than a second predetermined temperature threshold, if thecurrent charging mode is the second charging mode, the second chargingmode is switched to the first charging mode. The first predeterminedtemperature threshold is greater than the second predeterminedtemperature threshold. In other words, when the temperature of thebattery is too low (for example, corresponding to less than the secondpredetermined temperature threshold) or too high (for example,corresponding to greater than the first predetermined temperaturethreshold), it is unsuitable to perform the second charging, such thatit needs to switch from the second charging mode to the first chargingmode. In embodiments of the present disclosure, the first predeterminedtemperature threshold and the second predetermined temperature thresholdcan be set according to actual situations.

In an embodiment of the present disclosure, the switch unit iscontrolled to switch off when the temperature of the battery is greaterthan a predetermined high temperature protection threshold. Namely, whenthe temperature of the battery exceeds the high temperature protectionthreshold, it needs to apply a high temperature protection strategy tocontrol the switch unit to switch off, such that the power adapter stopscharging the battery, thus realizing the high protection of the batteryand improving the safety of charging. The high temperature protectionthreshold may be different from or the same to the first temperaturethreshold. In an embodiment, the high temperature protection thresholdis greater than the first temperature threshold.

In another embodiment of the present disclosure, the terminal furtherobtains the temperature of the battery, and controls to stop chargingthe battery (for example by controlling a charging control switch toswitch off at the terminal side) when the temperature of the battery isgreater than the predetermined high temperature protection threshold, soas to stop the charging process of the battery and to ensure the safetyof charging.

Moreover, in an embodiment of the present disclosure, the chargingmethod further includes: obtaining a temperature of the first charginginterface, and controlling the switch unit to switch off when thetemperature of the first charging interface is greater than apredetermined protection temperature. In other words, when thetemperature of the charging interface exceeds a certain temperature, thecontrol unit needs to apply the high temperature protection strategy tocontrol the switch unit to switch off, such that the power adapter stopscharging the battery, thus realizing the high protection of the batteryand improving the safety of charging.

Certainly, in another embodiment of the present disclosure, the terminalobtains the temperature of the first charging interface by performingthe bidirectional communication with the power adapter via the secondcharging interface. When the temperature of the first charging interfaceis greater than the predetermined protection temperature, the terminalcontrols the charging control switch to switch off, i.e., the chargingcontrol switch can be switched off at the terminal side, so as to stopthe charging process of the battery, thus ensuring the safety ofcharging.

During a process that the power adapter charges the terminal, the switchunit is controlled to switch off when the voltage sampling value isgreater than a second predetermined voltage value. Namely, adetermination is performed on the voltage sampling value during theprocess that the power adapter charges the terminal. When the voltagesampling value is greater than the second predetermined voltage value,it indicates that the voltage outputted by the power adapter is toohigh. At this time, the power adapter is controlled to stop charging theterminal by controlling the switch unit to switch off. In other words,the over-voltage protection of the power adapter is realized bycontrolling the switch unit to switch off, thus ensuring the safety ofcharging.

Certainly, in an embodiment of the present disclosure, the terminalobtains the voltage sampling value by performing a bidirectionalcommunication with the power adapter via the second charging interface,and controls to stop charging the battery when the voltage samplingvalue is greater than the second predetermined voltage value. Namely,the charging control switch is controlled to switch off at the terminalside, so as to stop the charging process, such that the safety ofcharging can be ensured.

In an embodiment of the present disclosure, during the process that thepower adapter charges the terminal, the switch unit is controlled toswitch off when the current sampling value is greater than apredetermined current value. In other words, during the process that thepower adapter charges the terminal, a determination is performed on thecurrent sampling value. When the current sampling value is greater thanthe predetermined current value, it indicates that the current outputtedby the power adapter is too high. At this time, the power adapter iscontrolled to stop charging the terminal by controlling the switch unitto switch off. In other words, the over-current protection of the poweradapter is realized by controlling the switch unit to switch off, thusensuring the safety of charging.

Similarly, the terminal obtains the current sampling value by performingthe bidirectional communication with the power adapter via the secondcharging interface, and controls to stop charging the battery when thecurrent sampling value is greater than the predetermined current value.In other words, the charging control switch is controlled to be switchedoff at the terminal side, such that the charging process of the batteryis stopped, thus ensuring the safety of charging.

The second predetermined voltage value and the predetermined currentvalue may be set according to actual situations.

In embodiments of the present disclosure, the status information of theterminal includes the electric quantity of the battery, the temperatureof the battery, the voltage/current of the battery of the terminal,interface information of the terminal and information on a pathimpedance of the terminal.

In detail, the power adapter can be coupled to the terminal via auniversal serial bus (USB) interface. The USB interface may be a generalUSB interface, or a micro USB interface. A data wire in the USBinterface is configured as the data wire in the first charginginterface, and configured for the bidirectional communication betweenthe power adapter and the terminal The data wire may be D+ and/or D−wire in the USB interface. The bidirectional communication may refer toan information interaction performed between the power adapter and theterminal.

The power adapter performs the bidirectional communication with theterminal via the data wire in the USB interface, so as to determine tocharge the terminal in the second charging mode.

As an embodiment, when the power adapter performs the bidirectionalcommunication with the terminal via the first charging interface so asto determine to charge the terminal in the second charging mode, thepower adapter sends a first instruction to the terminal. The firstinstruction is configured to query the terminal whether to operate inthe second charging mode. The power adapter receives a first replyinstruction from the terminal. The first reply instruction is configuredto indicate that the terminal agrees to operate in the second chargingmode.

As an embodiment, before the power adapter sends the first instructionto the terminal, the power adapter charges the terminal in the firstcharging mode. When the power adapter determines that a chargingduration of the first charging mode is greater than a predeterminedthreshold, the power adapter sends the first instruction to theterminal.

In an embodiment, when the power adapter determines that a chargingduration of the first charging mode is greater than a predeterminedthreshold, the power adapter may determine that the terminal hasidentified it as a power adapter, such that the second charging querycommunication may start.

As an embodiment, the power adapter is controlled to adjust a chargingcurrent to a charging current corresponding to the second charging modeby controlling the switch unit. Before the power adapter charges theterminal with the charging current corresponding to the second chargingmode, a bidirectional communication is performed with the terminal viathe first charging interface to determine a charging voltagecorresponding to the second charging mode, and the power adapter iscontrolled to adjust a charging voltage to the charging voltagecorresponding to the second charging mode.

As an embodiment, performing the bidirectional communication with theterminal via the first charging interface to determine the chargingvoltage corresponding to the second charging mode includes: sending bythe power adapter a second instruction to the terminal, receiving by thepower adapter a second reply instruction sent from the terminal, anddetermining by the power adapter the charging voltage corresponding tothe second charging mode according to the second reply instruction. Thesecond instruction is configured to query whether a current outputvoltage of the power adapter is suitable for being used as the chargingvoltage corresponding to the second charging mode. The second replyinstruction is configured to indicate that the current output voltage ofthe power adapter is suitable, high or low.

As an embodiment, before controlling the power adapter to adjust thecharging current to the charging current corresponding to the secondcharging mode, the charging current corresponding to the second chargingmode is determined by performing the bidirectional communication withthe terminal via the first charging interface.

As an embodiment, determining the charging current corresponding to thesecond charging mode by performing the bidirectional communication withthe terminal via the first charging interface includes: sending by thepower adapter a third instruction to the terminal, receiving by thepower adapter a third reply instruction sent from the terminal anddetermining by the power adapter the charging current corresponding tothe second charging mode according to the third reply instruction. Thethird instruction is configured to query a maximum charging currentsupported by the terminal The third reply instruction is configured toindicate the maximum charging current supported by the terminal.

The power adapter may determine the above maximum charging current asthe charging current corresponding to the second charging mode, or mayset the charging current as a charging current less than the maximumcharging current.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the bidirectional communication isperformed with the terminal via the first charging interface, so as tocontinuously adjust a charging current outputted to the battery from thepower adapter by controlling the switch unit.

The power adapter may query the status information of the terminalcontinuously, so as to adjust the charging current continuously, forexample, query the voltage of the battery of the terminal, the electricquantity of the battery, etc.

As an embodiment, performing the bidirectional communication with theterminal via the first charging interface to continuously adjust thecharging current outputted to the battery from the power adapter bycontrolling the switch unit includes: sending by the power adapter afourth instruction to the terminal, receiving by the power adapter afourth reply instruction sent by the terminal, and adjusting thecharging current by controlling the switch unit according to the currentvoltage of the battery. The fourth instruction is configured to query acurrent voltage of the battery in the terminal. The fourth replyinstruction is configured to indicate the current voltage of the batteryin the terminal.

As an embodiment, adjusting the charging current by controlling theswitch unit according to the current voltage of the battery includes:adjusting the charging current outputted to the battery from the poweradapter to a charging current value corresponding to the current voltageof the battery by controlling the switch unit according to the currentvoltage of the battery and a predetermined correspondence betweenbattery voltage values and charging current values.

In detail, the power adapter may store the correspondence betweenbattery voltage values and charging current values in advance.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, it is determined whether there isa poor contact between the first charging interface and the secondcharging interface by performing the bidirectional communication withthe terminal via the first charging interface. When it is determinedthat there is the poor contact between the first charging interface andthe second charging interface, the power adapter is controlled to quitthe second charging mode.

As an embodiment, before determining whether there is the poor contactbetween the first charging interface and the second charging interface,the power adapter receives information indicating a path impedance ofthe terminal from the terminal. The power adapter sends a fourthinstruction to the terminal. The fourth instruction is configured toquery a current voltage of the battery in the terminal. The poweradapter receives a fourth reply instruction sent by the terminal. Thefourth reply instruction is configured to indicate the current voltageof the battery in the terminal. The power adapter determines a pathimpedance from the power adapter to the battery according to an outputvoltage of the power adapter and the current voltage of the battery anddetermines whether there is the poor contact between the first charginginterface and the second charging interface according to the pathimpedance from the power adapter to the battery, the path impedance ofthe terminal, and a path impedance of a charging wire between the poweradapter and the terminal.

As an embodiment, before the power adapter is controlled to quit thesecond charging mode, a fifth instruction is sent to the terminal. Thefifth instruction is configured to indicate that there is the poorcontact between the first charging interface and the second charginginterface.

After sending the fifth instruction, the power adapter may quit thesecond charging mode or reset.

The second charging process according to embodiments of the presentdisclosure is described from the perspective of the power adapter, andthen the second charging process according to embodiments of the presentdisclosure will be described from the perspective of the terminal in thefollowing.

In embodiments of the present disclosure, the terminal supports thefirst charging mode and the second charging mode. The charging currentof the second charging mode is greater than that of the first chargingmode. The terminal performs the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter determines to charge the terminal in the second charging mode.The power adapter outputs according to a charging current correspondingto the second charging mode, for charging the battery in the terminal.

As an embodiment, performing by the terminal the bidirectionalcommunication with the power adapter via the second charging interfacesuch that the power adapter determines to charge the terminal in thesecond charging mode includes: receiving by the terminal the firstinstruction sent by the power adapter, in which the first instruction isconfigured to query the terminal whether to operate in the secondcharging mode; sending by the terminal a first reply instruction to thepower adapter. The first reply instruction is configured to indicatethat the terminal agrees to operate in the second charging mode.

As an embodiment, before the terminal receives the first instructionsent by the power adapter, the battery in the terminal is charged by thepower adapter in the first charging mode. When the power adapterdetermines that a charging duration of the first charging mode isgreater than a predetermined threshold, the terminal receives the firstinstruction sent by the power adapter.

As an embodiment, before the power adapter outputs according to thecharging current corresponding to the second charging mode for chargingthe battery in the terminal, the terminal performs the bidirectionalcommunication with the power adapter via the second charging interface,such that the power adapter determines the charging voltagecorresponding to the second charging mode.

As an embodiment, performing by the terminal the bidirectionalcommunication with the power adapter via the second charging interfacesuch that the power adapter determines the charging voltagecorresponding to the second charging mode includes: receiving by theterminal a second instruction sent by the power adapter, and sending bythe terminal a second reply instruction to the power adapter. The secondinstruction is configured to query whether a current output voltage ofthe power adapter is suitable for being used as the charging voltagecorresponding to the second charging mode. The second reply instructionis configured to indicate that the current output voltage of the poweradapter is suitable, high or low.

As an embodiment, before the terminal receives the charging currentcorresponding to the second charging mode from the power adapter forcharging the battery in the terminal, the terminal performs thebidirectional communication with the power adapter via the secondcharging interface, such that the power adapter determines the chargingcurrent corresponding to the second charging mode.

Performing by the terminal the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter determines the charging current corresponding to the secondcharging mode includes: receiving by the terminal a third instructionsent by the power adapter, in which the third instruction is configuredto query a maximum charging current supported by the terminal; sendingby the terminal a third reply instruction to the power adapter, in whichthe third reply instruction is configured to indicate the maximumcharging current supported by the terminal, such that the power adapterdetermines the charging current corresponding to the second chargingmode according to the maximum charging current.

As an embodiment, during a process that the power adapter charges theterminal in the second charging mode, the terminal performs thebidirectional communication with the power adapter via the secondcharging interface, such that the power adapter continuously adjusts acharging current outputted to the battery.

Performing by the terminal the bidirectional communication with thepower adapter via the second charging interface such that the poweradapter continuously adjusts a charging current outputted to the batteryincludes: receiving by the terminal a fourth instruction sent by thepower adapter, in which the fourth instruction is configured to query acurrent voltage of the battery in the terminal; sending by the terminala fourth reply instruction to the power adapter, in which the fourthreply instruction is configured to indicate the current voltage of thebattery in the terminal, such that the power adapter continuouslyadjusts the charging current outputted to the battery according to thecurrent voltage of the battery.

As an embodiment, during the process that the power adapter charges theterminal in the second charging mode, the terminal performs thebidirectional communication with the control unit, such that the poweradapter determines whether there is a poor contact between the firstcharging interface and the second charging interface.

Performing by the terminal the bidirectional communication with thepower adapter, such that the power adapter determines whether there isthe poor contact between the first charging interface and the secondcharging interface includes: receiving by the terminal a fourthinstruction sent by the power adapter, in which the fourth instructionis configured to query a current voltage of the battery in the terminal;sending by the terminal a fourth reply instruction to the power adapter,in which the fourth reply instruction is configured to indicate thecurrent voltage of the battery in the terminal, such that the poweradapter determines whether there is the poor contact between the firstcharging interface and the second charging interface according to anoutput voltage of the power adapter and the current voltage of thebattery.

As an embodiment, the terminal receives a fifth instruction sent by thepower adapter. The fifth instruction is configured to indicate thatthere is the poor contact between the first charging interface and thesecond charging interface.

In order to initiate and adopt the second charging mode, the poweradapter may perform a second charging communication procedure with theterminal, for example, by one or more handshakes, so as to realize thesecond charging of battery. Referring to FIG. 6, the second chargingcommunication procedure according to embodiments of the presentdisclosure and respective stages in the second charging process will bedescribed in detail. It should be understood that, communication actionsor operations illustrated in FIG. 6 are merely exemplary. Otheroperations or various modifications of respective operations in FIG. 6can be implemented in embodiments of the present disclosure. Inaddition, respective stages in FIG. 6 may be executed in an orderdifferent from that illustrated in FIG. 6, and it is unnecessary toexecute all the operations illustrated in FIG. 6. It should be notedthat, a curve in FIG. 6 represents a variation trend of a peak value ora mean value of the charging current, rather than a curve of actualcharging current.

In conclusion, with the charging method according to embodiments of thepresent disclosure, the power adapter is controlled to output the thirdvoltage with the third ripple waveform which meets the chargingrequirement, and the third voltage with the third ripple waveformoutputted by the power adapter is directly applied to the battery of theterminal, thus realizing second charging to the battery directly by theripple output voltage/current. In contrast to the constant voltage andconstant current, a magnitude of the ripple output voltage/currentchanges periodically, such that a lithium precipitation of the lithiumbattery may be reduced, the service life of the battery may be improved,and a probability and intensity of arc discharge of a contact of acharging interface may be reduced, the service life of the charginginterface may be prolonged, and it is beneficial to reduce polarizationeffect of the battery, improve charging speed, and decrease heat emittedby the battery, thus ensuring a reliability and safety of the terminalduring the charging. Moreover, since the power adapter outputs thevoltage with the ripple waveform, it is unnecessary to provide anelectrolytic condenser in the power adapter, which not only realizessimplification and miniaturization of the power adapter, but alsodecreases cost greatly.

In the specification of the present disclosure, it is to be understoodthat terms such as “central,” “longitudinal,” “lateral,” “length,”“width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,”“right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,”“clockwise,” “counterclockwise,” “axial,” “radial,” and “circumference”refer to the orientations and location relations which are theorientations and location relations illustrated in the drawings, and fordescribing the present disclosure and for describing in simple, andwhich are not intended to indicate or imply that the device or theelements are disposed to locate at the specific directions or arestructured and performed in the specific directions, which could not tobe understood to the limitation of the present disclosure.

In addition, terms such as “first” and “second” are used herein forpurposes of description and are not intended to indicate or implyrelative importance or significance or to imply the number of indicatedtechnical features. Thus, the feature defined with “first” and “second”may comprise one or more of this feature. In the description of thepresent disclosure, “a plurality of” means two or more than two, unlessspecified otherwise.

In the present disclosure, unless specified or limited otherwise, theterms “mounted,” “connected,” “coupled,” “fixed” and the like are usedbroadly, and may be, for example, fixed connections, detachableconnections, or integral connections; may also be mechanical orelectrical connections; may also be direct connections or indirectconnections via intervening structures; may also be inner communicationsof two elements, which can be understood by those skilled in the artaccording to specific situations.

In the present disclosure, unless specified or limited otherwise, astructure in which a first feature is “on” or “below” a second featuremay include an embodiment in which the first feature is in directcontact with the second feature, and may also include an embodiment inwhich the first feature and the second feature are not in direct contactwith each other, but are contacted via an additional feature formedtherebetween. Furthermore, a first feature “on,” “above,” or “on top of”a second feature may include an embodiment in which the first feature isright or obliquely “on,” “above,” or “on top of” the second feature, orjust means that the first feature is at a height higher than that of thesecond feature; while a first feature “below,” “under,” or “on bottomof” a second feature may include an embodiment in which the firstfeature is right or obliquely “below,” “under,” or “on bottom of” thesecond feature, or just means that the first feature is at a heightlower than that of the second feature.

Reference throughout this specification to “an embodiment,” “someembodiments,” “one embodiment”, “another example,” “an example,” “aspecific example,” or “some examples,” means that a particular feature,structure, material, or characteristic described in connection with theembodiment or example is included in at least one embodiment or exampleof the present disclosure. Thus, the appearances of the phrases such as“in some embodiments,” “in one embodiment”, “in an embodiment”, “inanother example,” “in an example,” “in a specific example,” or “in someexamples,” in various places throughout this specification are notnecessarily referring to the same embodiment or example of the presentdisclosure. Furthermore, the particular features, structures, materials,or characteristics may be combined in any suitable manner in one or moreembodiments or examples.

Those skilled in the art may be aware that, in combination with theexamples described in the embodiments disclosed in this specification,units and algorithm steps can be implemented by electronic hardware, ora combination of computer software and electronic hardware. In order toclearly illustrate interchangeability of the hardware and software,components and steps of each example are already described in thedescription according to the function commonalities. Whether thefunctions are executed by hardware or software depends on particularapplications and design constraint conditions of the technicalsolutions. Persons skilled in the art may use different methods toimplement the described functions for each particular application, butit should not be considered that the implementation goes beyond thescope of the present disclosure.

Those skilled in the art may be aware that, with respect to the workingprocess of the system, the device and the unit, reference is made to thepart of description of the method embodiment for simple and convenience,which are described herein.

In embodiments of the present disclosure, it should be understood that,the disclosed system, device and method may be implemented in other way.For example, embodiments of the described device are merely exemplary.The partition of units is merely a logical function partitioning. Theremay be other partitioning ways in practice. For example, several unitsor components may be integrated into another system, or some featuresmay be ignored or not implemented. Further, the coupling between eachother or directly coupling or communication connection may beimplemented via some interfaces. The indirect coupling or communicationconnection may be implemented in an electrical, mechanical or othermanner.

In embodiments of the present disclosure, it should be understood that,the units illustrated as separate components can be or not be separatedphysically, and components described as units can be or not be physicalunits, i.e., can be located at one place, or can be distributed ontomultiple network units. It is possible to select some or all of theunits according to actual needs, for realizing the objective ofembodiments of the present disclosure.

In addition, each functional unit in the present disclosure may beintegrated in one progressing module, or each functional unit exists asan independent unit, or two or more functional units may be integratedin one module.

If the integrated module is embodied in software and sold or used as anindependent product, it can be stored in the computer readable storagemedium. Based on this, the technical solution of the present disclosureor a part making a contribution to the related art or a part of thetechnical solution may be embodied in a manner of software product. Thecomputer software produce is stored in a storage medium, including someinstructions for causing one computer device (such as a personal PC, aserver, or a network device etc.) to execute all or some of steps of themethod according to embodiments of the present disclosure. Theabove-mentioned storage medium may be a medium able to store programcodes, such as, USB flash disk, mobile hard disk drive (mobile HDD),read-only memory (ROM), random-access memory (RAM), a magnetic tape, afloppy disc, an optical data storage device, and the like.

Although explanatory embodiments have been illustrated and described, itwould be appreciated by those skilled in the art that the aboveembodiments cannot be construed to limit the present disclosure, andchanges, alternatives, and modifications can be made in the embodimentswithout departing from spirit, principles and scope of the presentdisclosure.

What is claimed is:
 1. A charging system, comprising: a battery; a firstrectifier, configured to rectify an input alternating current and outputa first voltage with a first ripple waveform; a switch unit, configuredto modulate the first voltage according to a control signal and output amodulated first voltage; a transformer, configured to output a secondvoltage with a second ripple waveform according to the modulated firstvoltage; a second rectifier, configured to rectify the second voltage tooutput a third voltage with a third ripple waveform; a sampling unit,configured to sample current outputted by the second rectifier to obtaina current sampling value; and a control unit, coupled to the samplingunit and the switch unit respectively, and configured to output thecontrol signal to the switch unit, and to control a charging process tobe in a constant current charging stage by adjusting a duty ratio of thecontrol signal when it is determined that current outputted is high orlow according to the current sampling value wherein the third voltage isapplied to the battery.
 2. A power adapter, comprising: a firstrectifier, configured to rectify an input alternating current and outputa first voltage with a first ripple waveform; a switch unit, configuredto modulate the first voltage according to a control signal and output amodulated first voltage; a transformer, configured to output a secondvoltage with a second ripple waveform according to the modulated firstvoltage; a second rectifier, configured to rectify the second voltage tooutput a third voltage with a third ripple waveform, wherein the thirdvoltage is configured to be introduced into a terminal to charge abattery in the terminal when the power adapter is coupled to theterminal; a sampling unit, configured to sample current outputted by thesecond rectifier to obtain a current sampling value; and a control unit,coupled to the sampling unit and the switch unit respectively, andconfigured to output the control signal to the switch unit, and tocontrol a charging process performed by the power adapter on a terminalto be in a constant current charging stage by adjusting a duty ratio ofthe control signal when it is determined that current outputted by thepower adapter is high or low according to the current sampling value. 3.The power adapter according to claim 2, wherein the control unit isconfigured to reduce the duty ratio of the control signal when thecurrent outputted by the power adapter is high, and to increase the dutyratio of the control signal when the current outputted by the poweradapter is low.
 4. The power adapter according to claim 2, wherein thesampling unit is further configured to sample voltage outputted by thesecond rectifier to obtain a voltage sampling value.
 5. The poweradapter according to claim 4, wherein after the constant currentcharging stage is completed, the control unit is further configured tocontrol the charging process performed by the power adapter on theterminal to be in a constant voltage charging stage by adjusting theduty ratio of the control signal when it is determined that voltageoutputted by the power adapter is high or low according to the voltagesampling value.
 6. The power adapter according to claim 5, wherein thecontrol unit is configured to reduce the duty ratio of the controlsignal when the voltage outputted by the power adapter is high, and toincrease the duty ratio of the control signal when the voltage outputtedby the power adapter is low.
 7. The power adapter according to claim 4,wherein the sampling unit comprises: a first current sampling circuit,configured to sample the current outputted by the second rectifier so asto obtain the current sampling value; and a first voltage samplingcircuit, configured to sample the voltage outputted by the secondrectifier so as to obtain the voltage sampling value.
 8. The poweradapter according to claim 7, wherein the first voltage sampling circuitcomprises: a peak voltage sampling and holding unit, configured tosample and hold a peak voltage of the third voltage; a cross-zerosampling unit, configured to sample a zero crossing point of the thirdvoltage; a leakage unit, configured to perform a leakage on the peakvoltage sampling and holding unit at the zero crossing point; and an ADsampling unit, configured to sample the peak voltage in the peak voltagesampling and holding unit so as to obtain the voltage sampling value. 9.The power adapter according to claim 2, wherein the power adaptercomprises a first charging interface, the first charging interfacecomprises: a power wire, configured to charge the battery; and a datawire, configured to communicate with the terminal when the power adapteris coupled to the terminal via the first charging interface.
 10. Thepower adapter according to claim 9, wherein the control unit isconfigured to communicate with the terminal via the first charginginterface to determine a charging mode, in which the charging modecomprises a second charging mode and a first charging mode, and thesecond charging mode is different from the first charging mode.
 11. Thepower adapter according to claim 10, wherein when the control unitperforms the bidirectional communication with the terminal via the datawire of the first charging interface to determine to charge the terminalin the second charging mode, the control unit is configured to send afirst instruction to the terminal, in which the first instruction isconfigured to query the terminal whether to operate in the secondcharging mode; and the control unit is configured to receive a firstreply instruction from the terminal, in which the first replyinstruction is configured to indicate that the terminal agrees tooperate in the second charging mode.
 12. The power adapter according toclaim 11, wherein, the control unit is configured to send the firstinstruction to the terminal when it is determined that a chargingduration of the first charging mode is greater than a predeterminedthreshold.
 13. The power adapter according to claim 11, wherein thecontrol unit is further configured to control the power adapter toadjust a charging current to a charging current corresponding to thesecond charging mode by controlling the switch unit, and before thepower adapter charges the terminal with the charging currentcorresponding to the second charging mode, the control unit isconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface to determine acharging voltage corresponding to the second charging mode, and tocontrol the power adapter to adjust a charging voltage to the chargingvoltage corresponding to the second charging mode.
 14. The power adapteraccording to claim 13, wherein when the control unit performs thebidirectional communication with the terminal via the data wire of thefirst charging interface to determine the charging voltage correspondingto the second charging mode, the control unit is configured to send asecond instruction to the terminal, in which the second instruction isconfigured to query whether a current output voltage of the poweradapter is suitable for being used as the charging voltage correspondingto the second charging mode; the control unit is configured to receive asecond reply instruction sent from the terminal, in which the secondreply instruction is configured to indicate that the current outputvoltage of the power adapter is suitable, high or low; and the controlunit is configured to determine the charging voltage corresponding tothe second charging mode according to the second reply instruction. 15.The power adapter according to claim 13, wherein, before controlling thepower adapter to adjust the charging current to the charging currentcorresponding to the second charging mode, the control unit is furtherconfigured to perform the bidirectional communication with the terminalvia the data wire of the first charging interface to determine thecharging current corresponding to the second charging mode.
 16. Thepower adapter according to claim 15, wherein, when the control unitperforms the bidirectional communication with the terminal via the datawire of the first charging interface to determines the charging currentcorresponding to the second charging mode, the control unit isconfigured to send a third instruction to the terminal, in which thethird terminal is configured to query a maximum charging currentsupported by the terminal; the control unit is configured to receive athird reply instruction sent from the terminal, in which the third replyinstruction is configured to indicate the maximum charging currentsupported by the terminal; and the control unit is configured todetermine the charging current corresponding to the second charging modeaccording to the third reply instruction.
 17. A charging method,comprising: performing a first rectification on a first alternatingcurrent to output a first voltage with a first ripple waveform;modulating the first voltage by controlling a switch unit, andoutputting a second voltage with a second ripple waveform by aconversion of a transformer; performing a second rectification on thesecond voltage to output a third voltage with a third ripple waveform,and applying the third voltage to a battery of the terminal; samplingcurrent after the second rectification to obtain a current samplingvalue; and controlling a charging process to be in a constant currentcharging stage by adjusting a duty ratio of a control signal forcontrolling the switch unit when it is determined that current outputtedis high or low according to the current sampling value.
 18. The chargingmethod according to claim 17, wherein adjusting a duty ratio of acontrol signal comprises: reducing the duty ratio of the control signalwhen the current outputted is high; and increasing the duty ratio of thecontrol signal when the current outputted is low.
 19. The chargingmethod according to claim 17, further comprising: communicating with aterminal so as to determine a charging mode, in which the charging modecomprises a second charging mode and a first charging mode, and thesecond charging mode is different from the first charging mode.
 20. Thecharging system according to claim 1, further comprising a terminal,wherein the battery is a component in the terminal.